The post Here’s Why You’re Getting Geometry Problems on GMAT Data Sufficiency Wrong appeared first on GMAT.
]]>I had a student recently whose Data Sufficiency (DS) accuracy was generally very high, and whose knowledge of geometry rules was solid. And yet, she was getting almost every geometry DS question wrong on practice tests!
This is actually very common: students who are otherwise good at geometry and/or DS struggle when the two things are put together.
Here are the 3 main reasons that students miss geometry DS problems:
Consider this problem:
If we want to know the area of the circle, we need to know the radius. Since we have a square inscribed in the circle, the diameter of the circle would be the diagonal of the square:
Therefore, if we have any length of the square – side length or diagonal – we can find the diameter of the circle, and thus the area. Statement (1) gives us a side length, and statement (2) gives the diagonal, so they’re both sufficient. The answer is D. Right?
Wrong.
There’s a major assumption that we just fell for here: we don’t know for sure that it’s a square! It looks like one, and it probably is, but we can’t assume anything. Some of the sides might be imperceptibly shorter than the others.
Just knowing one side length, as in statement (1), would not be enough to find the diameter if ABCD is not a square.
Statement (2) tells us that the line from A to C is the hypotenuse of a right triangle. By definition, the hypotenuse of any right triangle inscribed in a circle is also the diameter of the circle. If we have that diameter, we can solve for the radius and thus the area of the circle. The correct answer is B.
You have to prove it.
Don’t just rely on your eyes! Ask yourself if they’re given you enough information to PROVE that the shape is what it appears to be.
Try this problem:
You probably memorized the rule that the area of a rhombus is (diagonal_{1 }× diagonal_{2})/2. So you might start plugging the statement information into the problem to see if you can get the length of BG and AC, CE and DF.
If that’s the case, you might end up with E, which is a wrong answer.
Instead, start by asking yourself “why did they give me all of this given information?” If all we care about is the area of each rhombus, why did they bother giving us an equilateral triangle?? Before you dive into the statements, make every inference you can:
We could split each rhombus into 2 equilateral triangles:
Statement (1) gives us the area of the equilateral triangle. The area of each rhombus will be double that. Sufficient!
Statement (2) gives us a side length of one of the triangles. As we inferred, that’s enough. Sufficient! The correct answer is D.
Rephrasing in DS geometry = unpacking the diagram.
Even though it’s natural to want to plug all of the given information into the problem on geometry, it’s dangerous to dive into the statements right away. There may be a great deal of information already inferable from the diagram and the given information. You may think you need information from the statements that you could already have inferred from the diagram!
Always yourself – why is this piece of given information here? The GMAT will never give you anything in the question stem that’s not necessary to the problem.
In other DS problems (algebra, number properties, etc), you know to test cases to see if a statement is sufficient. You’d test one number, see what you get, then test another number to see if you get the same result.
For some reason, people don’t apply this same strategy to geometry. They draw one figure, then just stick with it. Instead, you want to try what we’ll call the Rubber Band Geometry Technique: imagine stretching and pulling the figure in different directions, as if it were made out of a Rubber Band.
Try this problem from the Manhattan Prep Advanced Quant Guide:
If you simply draw the first trapezoid that comes to mind, you might think that you have sufficient information with either of the statements alone. Instead, you have to think about all of the different ways that a circle could be tangent to 3 sides of a symmetrical trapezoid:
Statement (1): if the circle is tangent to both parallel sides (Figure A or B), then the diameter would be 10. But if the shape corresponds to figure C or D, the diameter would be less than 10. Insufficient.
Statement (2): Knowing the length of the shorter side is not sufficient. In Figures A & B, the diameter of the circle is less than the length of the shortest side. In Figures C and D, it’s greater. Insufficient.
Both statements: If the height is 10 but the shortest parallel side is 15, then Figures C and D are impossible. We’re left with Figures A and B, each of whose diameter is the same as the height: 10. Sufficient.
This problem would likely be impossible to get right without drawing the array of all possible configurations.
If they don’t give you a figure, try to draw several different ones with the given information. If they give you a figure, don’t assume it’s exactly to scale. You can still draw stretched or squished versions. Trapezoids, rectangles, isosceles triangles, and many other shapes can come in different dimensions.
How to improve on DS geometry:
Avoid these 3 common pitfalls by doing the following:
Want full access to Céilidh’s trove of GMAT knowledge? Try the first class of one of her upcoming GMAT courses absolutely free, no strings attached.
Céilidh Erickson is a Manhattan Prep instructor based on New York City. When she tells people that her name is pronounced “kay-lee,” she often gets puzzled looks. Céilidh is a graduate of Princeton University, where she majored in comparative literature. After graduation, tutoring was always the job that bought her the greatest joy and challenge, so she decided to make it her full-time job. Check out Céilidh’s upcoming GMAT courses (she scored a 760, so you’re in great hands).
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]]>The post MBA Admissions Myths Destroyed: Round 1 Is Everything appeared first on GMAT.
]]>Many MBA admissions officers will tell candidates that if they can complete their applications and submit them in Round 1, then they should do so. Most programs will also tell candidates that they should try to avoid Round 3, because the majority of the places in their classes will have been filled by then. So, what does that say about Round 2?
Candidates sometimes call mbaMission to ask whether submitting an application in Round 2 is worth the effort or whether the opportunity has passed at that point. Unfortunately, when one is being compared against a group of unknown competitors, being concerned about every perceived difference or deficiency is only natural. Some candidates grow concerned if they are a year older than the average at their target school, while others fret if they are a year younger. Many applicants worry if their GMAT score is ten points below a school’s average. And, of course, some worry if they submit their application in Round 2. However, the overall strength of your candidacy, which is a measure of many factors, is far more important than where you fit in relation to any single statistic—not to mention whether you apply in Round 1 or 2.
So, we too would encourage candidates to apply early, if they are ready, but we do not believe anyone should give up on their MBA dreams for a year if applying in Round 1 is just not practical. You may be surprised to discover that admissions committees encourage early applications but also concede that the difference in selectivity between the first and the second rounds is very small. To back up this statement, we offer a small selection of quotes from mbaMission’s exclusive interviews with admissions officers:
“People ask, generally, is it better to apply in the first round or the second round or third round? We definitely advise people to avoid the third round if possible, because space can become an issue by the time the third round rolls around. But we do view the first two rounds as roughly equivalent.” – Bruce DelMonico, Admissions Director, Yale School of Management
“[We] get about a third of our applications in Round 1, about 55% in Round 2, and the remainder in Round 3 … We encourage people to submit their application when they feel that they offer their best possible applications. … So, if you can get everything lined up and completed and you feel really good about it …, then I would encourage you to apply in Round 1. But if it takes you a bit longer, and you want to take the time to look at your application again and maybe have somebody else look at it, then Round 2 is fine, too.” – Soojin Kwon, Admissions Director, University of Michigan Ross School of Business
“We look at statistics over the years—how many applications we got, how many we admitted, and how many we yielded—and we try to even it out so we’re not being too generous in one round at the expense of another round.” – Dawna Clarke, Admissions Director, Dartmouth College Tuck School of Business
mbaMission is the leader in MBA admissions consulting with a full-time and comprehensively trained staff of consultants, all with profound communications and MBA experience. mbaMission has helped thousands of candidates fulfill their dream of attending prominent MBA programs around the world. Take your first step toward a more successful MBA application experience with a free 30-minute consultation with one of mbaMission’s senior consultants. Sign up today at www.mbamission.com/manhattangmat.
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]]>The post How Many Questions Can You Get Wrong on GMAT Quant? appeared first on GMAT.
]]>When you took tests in high school or college, your grade was based on the number of questions you got right. The only way to earn an A was by answering almost every question correctly. If you’ve been studying for a while, you’ve probably heard that the GMAT is different — but how different is it, really? You know that you’re supposed to miss questions on the GMAT, but how many can you actually miss on the Quant section and still get a good score?
I recently reviewed 15 randomly selected practice tests from a GMAT class I taught. These tests represent a wide range of ability levels. The GMAT Quant section is scored on a scale from 0 to 51, and the Quant scores I looked at ranged from 23 to 45. What I wanted to know was how many Quant questions students were actually missing.
Here are the results:
That’s crazy, right? The GMAT Quant section has 37 questions. If it were anything like a normal math test, the weakest test-takers would miss almost every question, and the strongest test-takers would get almost every question correct. But for some reason, everyone is missing almost the same number of questions.
Here’s why that happens. MBA admissions committees aren’t actually interested in whether you’re great at factoring quadratics, or whether you can recognize a misplaced modifier. They care much more about whether you can:
Because those are the skills that MBA programs care about, those are the skills the GMAT is designed to test. On the GMAT, the number of questions you get right or wrong doesn’t matter. In fact, the number of questions you get wrong on the Quant section has already been decided, before you take the test: it’s somewhere between 16 and 22 (most likely 18 or 19). What actually matters is which questions you get wrong, and when you get them wrong.
That’s what makes the difference between someone who misses 18 Quant questions and scores a 500, and someone who misses 18 Quant questions and scores a 700. The 500 scorer might miss most of the 18 questions in a row at the end, due to poor time management. The 700 scorer misses those 18 questions throughout the section — she misses roughly every other question. The 500 scorer regularly misses easy questions, whether that’s because she’s weak on the math basics, or because she makes careless errors. The 700 scorer misses hard questions, and she does so deliberately: if she’s probably going to get a question wrong, she chooses to get it wrong quickly and spend her resources elsewhere.
In short, you can miss 16-22 questions on the Quant section and still get a good score. But it’s just as easy to miss 16-22 questions on the Quant section and get a bad score. You aren’t going to miss just 5 or 10 questions, unless you’re hoping for a 99th percentile score — and possibly not even then! So, don’t worry about the number of questions you’re getting wrong, whether you’re studying or taking a practice test. Focus on increasing the difficulty of questions you can consistently get right, and on perfecting your test-taking strategy, and your score will improve even as your “grade” stays the same.
Want full access to Chelsey’s sage GMAT wisdom? Try the first class of one of her upcoming GMAT courses for absolutely free, no strings attached.
Chelsey Cooley is a Manhattan Prep instructor based in Seattle, Washington. Chelsey always followed her heart when it came to her education. Luckily, her heart led her straight to the perfect background for GMAT and GRE teaching: she has undergraduate degrees in mathematics and history, a master’s degree in linguistics, a 790 on the GMAT, and a perfect 170/170 on the GRE. Check out Chelsey’s upcoming GMAT prep offerings here.
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]]>The post GMATPrep Reading Comp: Tackling a Tough Passage (part 3) appeared first on GMAT.
]]>In the first installment of this series, we deconstructed a challenging Reading Comprehension passage from the GMATPrep free exams. Pull up that page, as I’m not going to repeat the full text of the passage here. (And if you’re just starting here, go through parts 1 and 2 first before you read this one!)
At the end of the second installment, I posted the second problem for the passage. Let’s figure it out!
Here it is again:
“According to the passage, which of the following is true of comparable worth as a policy?
“(A) Comparable worth policy decisions in pay-inequity cases have often failed to satisfy the complainants.
“(B) Comparable worth policies have been applied to both public-sector and private-sector employee pay schedules.
“(C) Comparable worth as a policy has come to be widely criticized in the past decade.
“(D) Many employers have considered comparable worth as a policy but very few have actually adopted it.
“(E) Early implementations of comparable worth policies resulted in only transitory gains in pay equity.”
What’s the first step?
Right, figure out what kind of RC problem this is. The language according to the passage signals that this is a Specific Detail question. On SD questions, your task is to find something that is specifically stated in the passage and “spit it back” to them as an answer.
So move to step 2: find the proof. What information do you need from the passage and where is that info located? The question stem asks what is true of comparable worth as a policy. Where do they talk about that?
The whole passage, of course, is about this CW idea, so it might be good to start by reminding yourself of what this idea is. It’s a way to help close pay gaps and it works well even when you’re dealing with different jobs, unlike some other methods.
Where, in general, does the passage detail the whole CW idea as a policy? Glance at your notes if needed; that was in paragraph 1. Review the text:
“Comparable worth, as a standard applied to eliminate inequities in pay, insists that the values of certain tasks performed in dissimilar jobs can be compared. In the last decade, this approach has become a critical social policy issue, as large numbers of private-sector firms and industries as well as federal, state, and local governmental entities have adopted comparable worth policies or begun to consider doing so.”
Now, I just want to caution you about something. The rest of the passage gets more at how CW has actually worked in practice (versus what the underlying policy is) and how it compares to some other policies. It’s possible that you’ll need info from one of those paragraphs to answer the question, but don’t go searching everything now. That’s a mistake—they’re trying to suck you into spending too much time.
Most likely, what you need is in paragraph 1, because paragraph 1 is where they discuss the overall policy, and that’s what the question specifically asks.
In short: start with the most likely paragraph. If that doesn’t work, you can decide at that point whether to look in another paragraph or whether to guess and move on. But don’t try to review the entire passage now; just go for the most likely paragraph.
Okay, step 3: try to predict what you need in the answer. There are a few bigdetails in this paragraph. CW applies when you’re talking about dissimilar jobs. This approach has become a critical social policy issue. (In this sense, critical means important, not negative. It’s critical that you study hard!) Finally, lots of organizations have started using CW or are considering doing so.
Now, you can take your final step: look at those answers and find a match.
“(A) Comparable worth policy decisions in pay-inequity cases have often failed to satisfy the complainants.”
This choice doesn’t match anything in paragraph 1, but could it be somewhere else in the passage? Wait! Don’t go searching yet. First, ask yourself: how does this choice fit in with the overall main point?
The main point of the passage was that this CW thing worked well in cases where other methods failed. CW didn’t fail (at least, not according to this passage). So this choice doesn’t fit with the main idea. Eliminate it.
“(B) Comparable worth policies have been applied to both public-sector and private-sector employee pay schedules.”
What does public-sector mean? That’s a synonym for government, as private-sector is typically a synonym for for-profit companies (whether the companies are privately-held or publicly-held). They do expect you to be familiar with this type of language, but note that they also gave you a clue in paragraph 1:
“…as large numbers of private-sector firms and industries as well as federal, state, and local governmental entities…”
They use the word private-sector in the passage, and they contrast that with governmental entities, so you can infer that the private ones are non-governmental. And then when you see public-sector, you can infer that this is the opposite of private, so this is a synonym for those governmental entities.
In short, this choice says that CW has been used by companies and by government groups. Hey! That’s exactly what paragraph 1 did say. This is the correct answer.
Do run your eye over the other answers, just to be thorough.
“(C) Comparable worth as a policy has come to be widely criticized in the past decade.”
Again, this doesn’t match with the main idea, which generally praises CW. No good.
“(D) Many employers have considered comparable worth as a policy but very few have actually adopted it.”
We call this one a Direct Contradiction trap. The passage says the opposite: large numbers of employees have adopted it or are considering doing so.
These Direct Contradiction traps can be really tempting when you don’t take the time to re-read the passage. You remember reading something about that…what was it again? And then you might fall into the trap of thinking that the passage said the opposite of what it really said.
“(E) Early implementations of comparable worth policies resulted in only transitory gains in pay equity.”
Transitory means temporary or not-long-lasting. If you don’t know the word, then pay attention to the word only: it signals some kind of a negative. Only (blank) gains in pay equity isn’t a good thing.
Paragraph 1 said nothing about early implementations of CW. It is possible that CW didn’t work as well early on. And if you hadn’t already found a good answer, maybe you’d go look elsewhere in the passage for a discussion of the early implementation. But since you already know that (B) works and since the point of the passage was really that this CW thing has generally worked well at least in the longer-term, cross this one off.
The correct answer is (B).
I want to summarize the process here, because a consistent process is really what’s going to help you most on these questions.
First, identify the question. According to the passage signals a Specific Detail question.
Second, find the proof. Figure out what you need to re-read in the passage in order to answer the question. (Do NOT skip this step. Do NOT rely on your memory. This is an open-book test! Re-read the needed material.)
Third, read that text and use it to formulate your own answer to the question. Your wording, of course, won’t match the wording of the correct answer. That’s okay. You’re just trying to articulate to yourself the kinds of things you want the answer to say or address. Get that clear in your head (or even jot down a note or two) before you go to the final step.
Fourth, eliminate wrong answers and find a match! This is what I want to emphasize here: look at how much work comes before you get to look at the answers. Don’t jump straight to the answers. Figure out what’s going on with the question first!
All right, are you ready for the third problem in the set? Here you go!
“Which of the following best describes an application of the principles of comparable worth as they are described in the passage?
“(A) The current pay, rates of increase, and rates of promotion for female mechanics are compared with those of male mechanics.
“(B) The training, skills, and experience of computer programmers in one division of a corporation are compared to those of programmers making more money in another division.
“(C) The number of women holding top executive positions in a corporation is compared to the number of women available for promotion to those positions, and both tallies are matched to the tallies for men in the same corporation.
“(D) The skills, training, and job responsibilities of the clerks in the township tax assessor’s office are compared to those of the much better-paid township engineers.
“(E) The working conditions of female workers in a hazardous-materials environment are reviewed and their pay schedules compared to those of all workers in similar environments across the nation.”
In the next installment of this series, we’ll talk about how to work your way through the above problem. I’ll also give you another new problem from the set.
(1) Follow the process. Don’t skip steps!
(2) Even though these are detail questions, you can still use the main idea / main point to help you eliminate answer choices. If something contradicts the main point, it’s probably incorrect (unless that question was worded in such a way as to contradict the main point: e.g., what would the author disagree with?).
(3) Reading Comp is an open-book test. The passage is always there while you’re answering questions. Don’t feel like you need to learn everything the first time you read it and don’t hesitate to go back to it whenever you need to do so.
* GMATPrep questions courtesy of the Graduate Management Admissions Council. Usage of this question does not imply endorsement by GMAC.
Can’t get enough of Stacey’s GMAT mastery? Attend the first session of one of her upcoming GMAT courses absolutely free, no strings attached. Seriously.
Stacey Koprince is a Manhattan Prep instructor based in Montreal, Canada and Los Angeles, California. Stacey has been teaching the GMAT, GRE, and LSAT for more than 15 years and is one of the most well-known instructors in the industry. Stacey loves to teach and is absolutely fascinated by standardized tests. Check out Stacey’s upcoming GMAT courses here.
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]]>The post Here’s What My Most Successful GMAT Students Have in Common appeared first on GMAT.
]]>After a few years of working with GMAT students, I’ve noticed a couple of trends among the super-successful — those who increase their GMAT score by 100 points, 200 points, or even more. Take a page out of these students’ books to increase your own GMAT studying efficiency.
Successful students have neat scratchwork
This isn’t always true, of course — I’ve known a number of students who hit the 700+ mark with horrible chickenscratch handwriting. But one thing I’ve noticed, from looking over the shoulders of many tutoring and classroom students, is that really successful GMAT test-takers often have neat, careful scratchwork. For one, it keeps them from making silly mistakes or wasting their own time when they have to reread what they’ve written down. Two, I suspect that keeping your writing organized helps to keep your thinking organized as well.
Successful students ask general questions
If you’re taking a GMAT class or working with a tutor, ask as many questions as you can! But remember that asking really great questions takes thought and practice. My most successful GMAT students don’t just ask questions about the problem we’re working on. They ask questions that generalize to other problems as well: what if this was a yes/no question instead? Could we use this on a problem with fractions instead of percents? Are all sentences with multiple modifiers ungrammatical, or is it just this one? Remember that every problem you do while you study for the GMAT is just that: a single problem. You definitely won’t see it verbatim on the test! But if you ask your teacher, or ask yourself, how to use the lessons from one problem to solve other ones, then you’re making real progress.
Successful students do each problem more than once.
Everyone should keep an error log. It doesn’t matter too much what your problem log looks like; what really matters is what you do with it. My most successful students are the ones who take the idea of problem logging and run with it. They don’t just record the problems they do and forget about them. They also mark down problems they’d like to redo, regardless of whether they got those problems right or wrong. Then, consistently, they go back and redo that list of problems and reanalyze them. If you get a problem wrong once, but are able to do it successfully afterwards, you’ve learned something useful. If you get a problem wrong (or take too long solving it) repeatedly, then something is going wrong and you should address it specifically. Is that problem ‘skippable’, or does it demonstrate an issue you need to address by studying?
All GMAT test-takers are different, and what works for one student might not work for another. But in my time at Manhattan Prep, I’ve watched a number of students increase their GMAT scores dramatically. When a student shows the three characteristics described in this article, I’m always more optimistic that he or she will gain a ton of points. If you want to improve your GMAT score massively, then on top of learning the GMAT content, do what the best students do: keep your work neat, generalize, and redo problems.
Want full access to Chelsey’s sage GMAT wisdom? Try the first class of one of her upcoming GMAT courses for absolutely free, no strings attached.
Chelsey Cooley is a Manhattan Prep instructor based in Seattle, Washington. Chelsey always followed her heart when it came to her education. Luckily, her heart led her straight to the perfect background for GMAT and GRE teaching: she has undergraduate degrees in mathematics and history, a master’s degree in linguistics, a 790 on the GMAT, and a perfect 170/170 on the GRE. Check out Chelsey’s upcoming GMAT prep offerings here.
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]]>The post Boring is Sometimes Best on GMAT Verbal appeared first on GMAT.
]]>There’s a particular exercise I like to do with students who overthink Reading Comprehension and Critical Reasoning problems. (I initially got it from fellow instructor Ceilidh Erickson, who developed this exercise for her own GMAT classes.) It involves answering GMAT RC and CR problems without looking at the passage or the argument. With a little training, my students can often reach 50% accuracy or better! That might seem impossible — but keep reading to learn the secret.
Four specific problem types on the GMAT reward boring, wishy-washy answers. Those problem types are as follows:
CR Assumption problems ask you to identify an argument’s background assumptions. There are always certain facts that an argument takes for granted. If one of these facts actually isn’t correct, then the argument won’t make logical sense. The right answer to an assumption problem, therefore, will be a statement that definitely has to be true in order for the argument to work. If an answer choice is “optional”, then the argument isn’t really assuming that it’s true, and it isn’t the right answer.
CR Draw a Conclusion problems also have you identify something that has to be true. This time, you’re choosing a conclusion that must be true, based solely on the facts in the argument. The right answer will be the only one that can be definitively proven using only the information from the argument, with a minimum of real-world knowledge.
RC Inference questions are very similar. The right answer always needs to be provable based on the passage. If there’s any way an answer choice could be false, it won’t be correct.
Finally, RC Main Idea questions are slightly different. You’re asked to choose an answer that accurately reflects what the whole Reading Comprehension passage does. The right answer won’t leave out any major parts of the passage, and it won’t add anything in — it won’t make any claims that the passage doesn’t make.
Notice what these problem types have in common. In the first three types, the right answer is something that has to be true. That’s a very high standard. If there’s even a single counterexample to an answer choice, then it doesn’t have to be true, and it won’t be the right answer. In the last problem type, the Main Idea question, the right answer can’t disagree with the passage in any detail. It also can’t leave out any major parts of the passage. That’s why the right answers to these problem types are generally weak, boring, and non-specific. It’s much easier to prove a weak, vague claim than a strong, specific one.
Give it a shot. Here are the answer choices that go with a particular CR Draw a Conclusion problem from the GMAC’s GMAT Prep software. Without having read the argument, which answer choices do you think would be easier to prove? Which would require quite a bit of evidence to prove?
(A) Individuals who are underweight do not run any risk of developing high levels of cholesterol in the bloodstream.
(B) Individuals who do not exercise regularly have a high risk of developing high levels of cholesterol in the bloodstream late in life.
(C) Exercise and weight reduction are the most effective methods of lowering bloodstream cholesterol levels in humans.
(D) A program of regular exercise and weight reduction lowers cholesterol levels in the bloodstream of some individuals.
(E) Only regular exercise is necessary to decrease cholesterol levels in the bloodstream of individuals of average weight.
Here are those answer choices again, with strong language in red, and wishy-washy language in green.
(A) Individuals who are underweight do not run any risk of developing high levels of cholesterol in the bloodstream.
(B) Individuals who do not exercise regularly have a high risk of developing high levels of cholesterol in the bloodstream late in life.
(C) Exercise and weight reduction are the most effective methods of lowering bloodstream cholesterol levels in humans.
(D) A program of regular exercise and weight reduction lowers cholesterol levels in the bloodstream of some individuals.
(E) Only regular exercise is necessary to decrease ch olesterol levels in the bloodstream of individuals of average weight.
(A), (C), and (E) would be pretty difficult to prove. For instance, to prove (C), the argument would have to somehow show that every other possible method was definitively less successful than exercise and weight reduction. It’s unlikely that a one-paragraph argument could do that! (D), on the other hand, intentionally makes a weak claim. It’s easy to prove that exercise and weight reduction work for some individuals, since you’d only need to show that it works for at least one person. And in fact, (D) is the correct answer.
Here’s another set of answer choices, this time from a RC Inference problem. This time, eliminate two answer choices that make excessively strong claims, without reading the passage.
With which of the following generalizations regarding management structures would the author of the passage most probably agree?
(A) Hierarchical management structures are the most efficient management structures possible in a modern context.
(B) Firms that routinely have a high volume of business transactions find it necessary to adopt hierarchical management structures.
(C) Hierarchical management structures cannot be successfully implemented without modern communications and transportation.
(D) Modern multinational firms with a relatively small volume of business transactions usually do not have hierarchically organized management structures.
(E) Companies that adopt hierarchical management structures usually do so in order to facilitate expansion into foreign trade.
If you chose to eliminate (A) and (C), you’re correct: neither of those is the right answer. (A) makes the powerful claim that one structure is the most efficient possible, while C claims that something cannot possibly happen. Both of those are unlikely to be provable based solely on the passage. The right answer is the much weaker (B), which hedges by specifying that only certain firms need to adopt hierarchical management.
Of course, you shouldn’t quit reading the passage when you do these problems on test day! But there are a few great ways to include this strategy in your GMAT practice. First, you can use it to double-check your answer. If you’re about to select an answer choice that makes a very strong or specific claim, be skeptical. If there isn’t equally strong evidence in the argument or passage to back up that strong claim, you’re probably falling for a trap. For practice, look through the answer choices to verbal problems from the Official Guide to the GMAT, and try to predict what answers are likely to be correct without reading the argument or passage. That’ll help you develop an intuitive feeling for right and wrong answers. You can even use the principle of “picking the boring answers” as a starting point on certain problems. Save time by identifying the answers that are most plausible first, then check the best answers against the text. Don’t bother checking the wrong-looking answers unless you’ve eliminated all of the right-looking ones.
Want full access to Chelsey’s sage GMAT wisdom? Try the first class of one of her upcoming GMAT courses for absolutely free, no strings attached.
Chelsey Cooley is a Manhattan Prep instructor based in Seattle, Washington. Chelsey always followed her heart when it came to her education. Luckily, her heart led her straight to the perfect background for GMAT and GRE teaching: she has undergraduate degrees in mathematics and history, a master’s degree in linguistics, a 790 on the GMAT, and a perfect 170/170 on the GRE. Check out Chelsey’s upcoming GMAT prep offerings here.
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]]>The post Two Minutes of GMAT Quant: A Breakdown (Part 3) appeared first on GMAT.
]]>Ready for the long awaited conclusion of how to tackle a quant problem in two minutes? We’ll finally get to the point where you can submit an answer! If you haven’t been keeping up, catch up here.
After thirty seconds, you know what the problem is asking, you’ve inserted some common sense, and you may have even eliminated some answer choices. Now it’s time to work efficiently.
If, in the first thirty seconds, you were able to see some equations fairly easily, meaning expressing the real world relationships as math doesn’t seem unreasonable, then it’s time to move into direct solving. Practice the first 30 seconds of analysis and then create whatever equations you can for this problem:
For every three boys, there are four girls in the group. If five boys join the group, and four girls leave the group, there will be an equal number of boys and girls in the group. How many boys are there initially?
Did you catch the answer choices that you could eliminate? Look again if you didn’t – there are two that are proven wrong with very little math.
We know that initially we have more girls than boys. Beyond that, we know the total number of boys, at least initially, is some multiple of three. (The initial number of girls is some multiple of four, but that’s less helpful since the answers are referring to the boys.) The right answer, therefore, must be a multiple of three. Experiment with different possible values of boys and girls keeping the ratio of three to four if you don’t quite see why. Once you’ve convinced yourself, eliminate answers (A) and (D), because they are not divisible by three.
From here, some of you out there will be able to read this problem, write the correct equations, and quickly solve. Excellent work. However, the many people have some trouble converting this situation into algebra. We’ll go through how in just a moment (and if you want an in-depth analysis of how to solve ratio problems like this one, check out our Fractions, Decimals, and Percents Strategy Guide), but let’s first play with the idea that the equations are either challenging or potentially incorrect.
As soon as you think direct algebra may be a waste of time, either because it will take too long or you’re not confident that you could do it correctly, consider alternative strategies. In this case, working backwards is a great choice. Céilidh, one of our instructors, has recently published a phenomenal post on how to determine when to work backwards, so feel free to check it out if you want more insight into this process.
Arguably the most important aspect of working backwards is organization, so consider creating a table to help yourself out. Let’s start with answer (B).
At this point, I often ask myself “What is the easiest thing to solve for next?” The beauty of working backwards is you select a series of simple steps, which eventually push you to either confirm or deny this answer choice as the correct answer. In this case, I think finding the number of boys after five more boys join is pretty easy. Let’s add that column to our table:
Again, what’s the easiest thing to solve for next? My vote is for the current number of girls because it’s the same as the current number of boys.
The only thing left to solve for is the initial number of girls, which we can get easily enough by adding 4 from the current number of girls.
The final step of working backwards is to compare the numbers we’ve calculated to what’s given to find whether this is correct or not. The only thing we haven’t used yet is the initial ratio of three boys to four girls in the group. For answer (B), the initial ratio is 21 to 30, which we can reduce to 7 to 10, but is not the same as 3 to 4. So let’s try another. How about C?
Try to fill in the rest of the chart and verify whether (C) is correct or not before reading on.
Our ratio is 27 to 36, which reduces to 9 to 12 aka 3 to 4. This is a perfect fit and C is the right answer.
Just as an aside, working backwards was much easier because we’d knocked out two answer choices from the start. We had a maximum of three choices to test.
Now, as promised, let’s work through algebraically. Here’s the question again:
For every three boys, there are four girls in the group. If five boys join the group, and four girls leave the group, there will be an equal number of boys and girls in the group. How many boys are there initially?
To start, you need to assign variables. Let’s make b and g the initial number of boys and girls in the group. We can express the ratio of three to four as b/g = 3/4. Now the tricky part. Five boys join the group, so we should create other variables for the new number of boys and girls. Try this:
b_{n }= b + 5 and g_{n} = g – 4. We now have four variables, which is way too many. We can break it down by using the last bit of information; the new number of boys equals the new number of girls, or, mathematically, b_{n }= g_{n}. This is very helpful, because it allows us to substitute our expressions for b_{n} and g_{n}, giving us two equations with two unknowns: b + 5 = g – 4 and b/g = 3/4. You can solve using substitution like so:
b/g = 3/4 so 4b = 3g and 4b/3 = g
b + 5 = g – 4 so substitute to get b + 5 = 4b/3 – 4 and solve for b to get 27.
Most problems can be solved multiple ways, like this one. As you start to work, be sure you are using the most efficient process, not just the most obvious ones.
Of course, the most in-depth way to learn the ins-and-outs of the GMAT is to take a complete course with one of our master instructors. You can try out any first session for free! No strings attached. We promise.
Emily Madan is a Manhattan Prep instructor based in Philadelphia. Having scored in the 99th percentile of the GMAT (770) and LSAT (177), Emily is committed to helping others achieve their full potential. In the classroom, she loves bringing concepts to life and her greatest thrill is that moment when a complex topic suddenly becomes clear to her students. Check out Emily’s upcoming GMAT courses here. Your first class is always free!
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]]>The post GMAT Sentence Correction Tests Good Grammar, Not Good Writing appeared first on GMAT.
]]>There’s a type of sentence known among linguists and grammar mavens as a “garden path” sentence. These sentences earned this name by leading readers “down the garden path” — you think the sentence is going in one direction, but halfway through, you suddenly realize that it’s saying something else entirely. Here’s the classic example:
The horse raced past the barn fell.
Believe it or not, this sentence is grammatically correct. The core of the sentence is The horse fell. “Raced past the barn” is just a modifier describing the horse. The sentence is equivalent to this one:
The horse that was raced past the barn fell.
The second sentence is written much more clearly. The phrase “that was” makes it obvious that a modifier is about to start, so you don’t expect raced to be the main verb of the sentence. Yet grammatically, they’re both technically fine. It’s okay to start modifiers with that was, but it’s also okay to start modifiers with just a past participle, like in these examples.
The man trampled by the horse has made a full recovery.
The mural created last year won several awards.
In English grammar, it’s often okay to leave out the that was or who was. Doing so sometimes leads to a poorly written or difficult to read sentence, which is why writers are cautious about it. But the GMAT tests grammar and logic, not clear writing. The right answers to GMAT Sentence Correction questions will sometimes phrase things in awkward-sounding or unclear ways.
Another example is the infamous appositive. Here’s a grammatically correct sentence from the GMAC’s GMATPrep software:
Architects and stonemasons, the Maya built huge palace and temple clusters without the benefit of animal transport or the wheel.
The phrase “architects and stonemasons” at the beginning of the sentence throws many readers off. It seems as if two nouns have been stuck onto the front of the sentence with no attention to how they fit in. This type of modifier — in which a noun, set off by commas, can modify another noun — sounds awkward to many readers. We almost never use appositives in speech, and many writers rarely use them. However, they’re acceptable in formal English grammar, and they’re acceptable on the GMAT.
In his recent self-help book, the author and diet guru proposed a revolutionary new way of losing weight, a method that allowed dieters to eat dessert after every meal and do only minimal exercise.
The phrase beginning with “a method” is also an appositive. Making matters worse, the appositive contains yet another modifier inside of it: that allowed… modifies method. Yet the sentence is still grammatically correct! You don’t need to memorize the technical details of this type of modifier, but you should remember that even if they sound strange, that’s just because they’re rare. They’re grammatically correct and okay on a GMAT Sentence Corrrection problem.
I’ll leave you with one last bizarre sentence. You might think that it’s never possible to have two verbs right next to each other! But this sentence would be correct on the GMAT:
The threat of dehydration that desert reptiles, such as the northern blue-tongued skink and the red diamond rattlesnake, face results from the dry and hot environment.
This sentence sounds strange because of the two verbs, face and results, that appear immediately next to each other. It’s also difficult to read because these two verbs can both also be used as nouns! However, structurally and grammatically, the sentence is correct. It actually has two modifiers nested inside of each other. The core is The threat of dehydration results from the dry and hot environment. The next phrase, that desert reptiles face, modifies threat of dehydration. And finally, such as the northern blue-tongued skink and the red diamond rattlesnake modifies reptiles.
The threat of dehydration that desert reptiles, such as the northern blue-tongued skink and the red diamond rattlesnake, face results from the dry and hot environment.
That’s a hideous sentence — but it’s not wrong. And what can you do about this? Here are three major ideas to use as you practice Sentence Correction:
To learn all things Sentence Correction, check out our Sentence Correction Strategy Guide.
Want full access to Chelsey’s sage GMAT wisdom? Try the first class of one of her upcoming GMAT courses for absolutely free, no strings attached.
Chelsey Cooley is a Manhattan Prep instructor based in Seattle, Washington. Chelsey always followed her heart when it came to her education. Luckily, her heart led her straight to the perfect background for GMAT and GRE teaching: she has undergraduate degrees in mathematics and history, a master’s degree in linguistics, a 790 on the GMAT, and a perfect 170/170 on the GRE. Check out Chelsey’s upcoming GMAT prep offerings here.
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]]>The post Taking the new mini-GMAT for EMBA? Here’s how to prep! – Part 2 appeared first on GMAT.
]]>Last time, we talked about the IR and Verbal sections of the new Executive Assessment (EA) exam for EMBA candidates. Today, we’re going to dive into Quant and also talk more about your overall study.
As I mentioned last time, not much has been released as of yet, so the conclusions we’re drawing are preliminary. This is what I would do if I had to take the test soon, given limited data. As more information and practice materials are released, we’ll update our thinking and approach.
The Quant section will consist of the same two question types (Problem Solving and Data Sufficiency) that appear on the Verbal section of the GMAT, but you’ll only have to answer 14 of them, not 37. You’ll be given 30 minutes or just over 2 minutes per question; this is about the same as on the GMAT.
The single biggest thing that I noticed: not one of the 15 released sample questions contains any geometry. This isn’t really surprising, since geometry doesn’t come into play at all in business school—but I’m still glad to see it. (Well…to not see it!)
Disclaimer: the absence of a particular topic from these 15 questions doesn’t automatically mean they won’t test it. In this case, though, we’re talking about an entire branch of mathematics! I think they would have included at least one geometry question if they were planning to test geometry on the EA.
As on the IR section, a number of the quant questions tested knowledge of percents (including percent change), fractions, and population growth / rate of change. This section did include some full-on rates material and I would expect ratios to be in the mix, as well as basic statistics: average, median, possibly some weighted average.
The sample questions do include algebra, but not some more advanced topics such as quadratic equations, functions, sequences, or absolute value. The algebra is limited to linear equations (you will, at times, have to translate words to math). This one is a bit harder to call: will they test exponents or roots, for example?
I don’t know, but I did notice that a large proportion of the questions dealt with real numbers. It seems that the EA is downplaying more “textbook” math and emphasizing stories that are a bit closer to how you would calculate something in real life. (Again, this makes sense, given the target audience for this exam.)
Several questions covered number properties topics, including divisibility and odd & even. I would guess that positive & negative will be fair game, too. I would imagine that they won’t get into combinatorics and possibly not probability—though that’s just a guess.
If you’ve studied for the GMAT and are familiar with the strategies Choose Smart Numbers and Test Cases, you can use these strategies on the EA, too. You also can (and should!) estimate at times. I would expect that other strategies, such as Work Backwards, will also come into play on the EA.
In short, it looks like the EA is mostly limited to concepts and strategies that we would, in fact, use in business school. Here’s what I would study from the books that we publish:
Foundations of Math: nearly everything! You can skip geometry, roots, quadratics, and absolute value.
Fractions, Decimals, & Percents: fractions, percents, ratios
Algebra: linear equations; the basics of exponents and inequalities
Word Problems: translations, statistics (average, median, weighted average), rates, population
Number Properties: divisibility and prime, odd and even, positive and negative
Geometry: nothing!
In our main strategy guides (everything but Foundations of Math), there are “Extra” chapters with more advanced material. Ignore all of those chapters.
Pretty much the same way you’d study if you were getting ready for the GMAT. You just don’t have to learn as much, thankfully. Learn the underlying rules and concepts, and then learn to think your way through GMAT-format questions.
It’s unclear at this point what kind of score will be considered competitive at various schools, so we’re all going into this a little bit blind right now. It has historically been the case that EMBA programs don’t place as much emphasis on standardized test scores as MBA programs, so I wouldn’t worry about trying to get an amazing score. You just want to do well enough that there aren’t any questions about your ability to handle the quantitative and analytical work that will be necessary once you start school.
If it were me, I’d plan for about 4 to 8 weeks of regular study—perhaps 1 hour a day Monday, Wednesday, Thursday, and then a couple of 1.5 to 2-hour sessions over the week-end. You could probably cram your studies into a shorter period of time, but your brain will retain the material better if you give it some time to sink in across multiple practice sessions. And you’ll likely be using most of the math concepts in business school, so you really do want to learn the material for real.
Are you planning to take the EA? Have you already taken it? Let us know about your experience in the comments. Good luck and happy studying!
Stacey Koprince is a Manhattan Prep instructor based in Montreal, Canada and Los Angeles, California. Stacey has been teaching the GMAT, GRE, and LSAT for more than 15 years and is one of the most well-known instructors in the industry. Stacey loves to teach and is absolutely fascinated by standardized tests. Check out Stacey’s upcoming GMAT courses here.
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]]>The post Think Like an Expert: How & When to Work Backwards on GMAT Problem Solving appeared first on GMAT.
]]>What does it take to be a GMAT expert? It’s not just content knowledge (although of course that’s necessary). A GMAT expert knows how to quickly identify patterns and choose quickly from a variety of strategies. In each of these segments, I’ll show you one of these expert moves and how to use it.
What working backwards is
Working backwards from the answer choices, back-solving, plug-and-chug… no matter what you call it, you’ve probably heard of it before. Many GMAT Problem Solving (PS) questions require laborious algebra to solve, but are much faster and easier to solve by simply plugging the answer choices into the problem to see what fits.
Try this problem:
Ada went to the supermarket with $36, expecting to buy a certain number of energy drinks. However, the store had recently raised the price of energy drinks by $1, causing Ada to purchase 3 fewer energy drinks than expected. How many energy drinks did she originally expect to purchase?
(A) 12
(B) 10
(C) 9
(D) 8
(E) 6
If you did the algebra, you probably ran into some really ugly, messy equations. If you picked numbers, you likely had a much easier time. (Explanations at the end)*
Here’s what I hear from students all the time: “oh, now that you showed me, I can see that working backwards is easier. But I didn’t even think to try it.”I blame high school teachers who made us show all of our work every time! We’re trained to think that algebra is the “right” way to do things, so we jump automatically into creating equations.
So, you’ll have to re-train yourself…
When are you allowed to work backwards?
Here’s the rule, and it’s pretty simple: you’re allowed to work backwards from the answer choices any time a PS question asks you for the value of an unknown (a variable) – in other words, if you could write the question as “x= ?,” you’re allowed to work backwards.
Working backwards usually does not work (or at least not easily) if the question asked for any other kind of information: a sum, a difference, a product, a ratio / proportion, a variable in terms of another variable, etc.
Consider the difference between these two ratio problems, and try working backwards for each:
At a certain animal shelter, the ratio of puppies to kittens on Monday was 4 to 5. During the week, 8 puppies and 7 kittens were adopted and left the shelter. If by Friday the ratio of remaining puppies to remaining kittens was 2 to 3, how many kittens were originally in the shelter on Monday?
(A) 18 (B) 20 (C) 25 (D) 27 (E) 30 |
At a certain animal shelter, the ratio of puppies to kittens on Monday was 4 to 5. During the week, 8 puppies and 7 kittens were adopted and left the shelter. If by Friday the ratio of remaining puppies to remaining kittens was 2 to 3, how many more kittens than puppies were originally in the shelter on Monday?
(A) 1 (B) 2 (C) 3 (D) 4 (E) 5 |
Question #1 asks for the original number of kittens, in other words the value of an unknown: k= ? We’re allowed to work backwards! We can easily plug in the answer choices into the original ratio (more on how to do so in a little bit).
Question #2 is asking for the difference between kittens and puppies. In other words, k – p= ? You probably had a lot more trouble working backwards on this one, so algebra probably was the most efficient strategy.
Train yourself to recognize working-backwards-problems
If you’re currently not using the strategy of working backwards because you “didn’t even think about it,” then you have to train yourself to recognize the signals.
Do this right now: grab a copy of the Official Guide. (If you don’t have one, you should definitely get one).
Step 1: Flip open to the first page of the PS section. Glance through the questions, and without solving, just ask yourself which questions you could work backwards on. In other words, which questions ask for the value of a variable? Write the question numbers down.
I’ll give you the first few from OG 2016: #3, #9, #12, #15, #19, #32. Now you practice recognizing the rest!
Step 2: Once you’re confident that you can recognize these problems, you can then go back and solve them by working backwards.
Step 3: Go back and re-solve these same questions, trying algebra this time. Then compare: which strategy was more efficient for you, and on which problems? This might vary from person to person, or topic to topic. Make sure you’re strengthening both muscles!
How to work backwards efficiently
Let’s go back to that first kittens-and-puppies problem. When you’re working backwards, it’s a good idea to create a chart to keep your information organized.
kittens: 5x | puppies: 4x | kittens – 7 | puppies – 8 | |
A | 18 | |||
B | 20 | |||
C | 25 | |||
D | 27 | |||
E | 30 |
Which answer choice should you start with? You’ll hear differing advice on this one: some people say to start with C, some say to start with B or D. The reasoning is that if you start with B and it’s too big, the answer must be A, and you can avoid testing a 2^{nd} value. If it’s too small, test D. If D is too small, the answer is E. If D is too large, the answer is C. This way, you’ve tested a maximum of 2 answers.
My recommendation, though, is to start with your intuition, then go with something else in the middle… whatever answer choice seems easiest. Just don’t start with A and test all 5 in a row, because you’ll be doing more work than you need to.
On this problem, intuition should tell you that if the original ratio of puppies to kitten was 4 to 5, the original number of kittens had to be a multiple of 5. We can rule out A and D. Then, I’d start with C, because it’s in the middle of the 3 answers I have left:
kittens: 5x | puppies: 4x | kittens – 7 | puppies – 8 | |
A | 18 | |||
B | 20 | |||
C | 25 | 20 | 18 | 12 |
D | 27 | |||
E | 30 |
If there were 25 kittens, there would have been 20 puppies to create a ratio of 4 to 5. If 7 kittens and 8 puppies leave, then the new ratio is 12 to 18, or 2 to 3. Correct!
Strategies are like muscles: you have to train them
Expert athletes don’t just know the rules of the game; they train themselves specifically to recognize and respond to different plays. If you want to become a GMAT expert, you need more than just knowing the rules: you need to train yourself on each individual skill.
Good luck!
*The algebraic solution:
Let p = expected price and q = expected quantity
pq = 36 and (p + 1)(q – 3) = 36
FOIL: pq – 3p + q – 3 = 36
Isolate: p = 36/q
Substitute: (36/q)q – 3(36/q) + q – 3 = 36
Simplify: 36 – 108/q + q – 3 = 36
Subtract 36 from both sides: – 108/q + q – 3 = 0
Multiply both sides by q: – 108 + q^{2} – 3q = 0
Rearrange: q^{2} – 3q – 108 = 0
Factor: (q – 12)(q + 9) = 0
Solve: q = 12 or -9 ⇒ it must be positive, so q = 12
Hideous and complicated! Let’s try working backwards. We can create a chart:
q | p | q – 3 | p + 1 | |
A | 12 | |||
B | 10 | |||
C | 9 | |||
D | 8 | |||
E | 6 |
Start with (B): 10 times what would equal 36? Nothing! Rule that out. Now try (C):
q | p | q – 3 | p + 1 | |
A | 12 | |||
B | 10 | |||
C | 9 | 4 | 6 | 5 |
D | 8 | |||
E | 6 |
6 × 5 is not 36, so rule that out. The number was too small, so try a bigger number, (A):
q | p | q – 3 | p + 1 | |
A | 12 | 3 | 9 | 4 |
B | 10 | |||
C | 9 | 4 | 6 | 5 |
D | 8 | |||
E | 6 |
9 × 4 = 36, so that works. (A) must be the answer!
Want full access to Céilidh’s trove of GMAT knowledge? Try the first class of one of her upcoming GMAT courses absolutely free, no strings attached.
Céilidh Erickson is a Manhattan Prep instructor based on New York City. When she tells people that her name is pronounced “kay-lee,” she often gets puzzled looks. Céilidh is a graduate of Princeton University, where she majored in comparative literature. After graduation, tutoring was always the job that bought her the greatest joy and challenge, so she decided to make it her full-time job. Check out Céilidh’s upcoming GMAT courses (she scored a 760, so you’re in great hands).
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