ToughNuthttp://tough-nut.blogspot.com/Puzzle based interview preparation resourceennoreply@blogger.com (Freddo)Thu, 15 Jun 2017 08:53:37 PDTBloggertag:blogger.com,1999:blog-716771017371742966430125Toughnuthttps://feedburner.google.comThe Camel & Bananashttp://feedproxy.google.com/~r/Toughnut/~3/u4prl4rlqao/camel-bananas.htmlbananascameloptimizationpuzzlenoreply@blogger.com (Freddo)Tue, 20 Mar 2012 04:00:00 PDTtag:blogger.com,1999:blog-7167710173717429664.post-85503687691737330902012-03-20T04:00:15.067-07:004You want to transport 3,000 bananas across 1,000 kilometers. You have a camel that can carry 1,000 bananas at most. However, the camel must eat 1 banana for each kilometer that it walks. What is the largest number of bananas that can be transported?
Can you solve it?
For extra credit, try deriving a general formula if you have B bananas, need to travel D distance, and the camel has a carrying capacity of C.
Source: mindyourdecisions.com <br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/u4prl4rlqao" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2012/03/camel-bananas.htmlCard Cashhttp://feedproxy.google.com/~r/Toughnut/~3/bCRJvKpeSK8/card-cash.htmlnoreply@blogger.com (Freddo)Wed, 22 Sep 2010 11:33:00 PDTtag:blogger.com,1999:blog-7167710173717429664.post-33559138026713772462010-09-22T11:33:34.330-07:008Someone offers you the following deal:
There is a deck of 100 initially blank cards. The dealer is allowed to write ANY positive integer, one per card, leaving none blank. You are then asked to turn over as many cards as you wish. If the last card you turn over is the highest in the deck, you win; otherwise, you lose.
Winning grants you $50, and losing costs you only the $10 you paid to play.
Would you accept this challenge?<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/bCRJvKpeSK8" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2010/09/card-cash.html29 hostages and a terroristhttp://feedproxy.google.com/~r/Toughnut/~3/z4i-ua5hNFg/29-hostages-and-terrorist.htmlnoreply@blogger.com (Freddo)Tue, 21 Sep 2010 10:45:00 PDTtag:blogger.com,1999:blog-7167710173717429664.post-66547198002673851752012-03-20T14:34:25.447-07:00429 hostages are captured by a terrorist. They are told, "You may meet today and plan a strategy. But after today, you will be in isolated cells and will have no communication with one another."
"There is an isolated switch room here, which contains two light switches labelled A and B, each of which can be in either the 'on' or the 'off' position. I am not telling you their present positions. The switches are not connected to anything."
"After today from time to time whenever I feel so...<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/z4i-ua5hNFg" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2010/09/29-hostages-and-terrorist.htmlHeads I win, Tails I lose.http://feedproxy.google.com/~r/Toughnut/~3/YhapILzg15g/heads-i-win-tails-i-lose.htmlnoreply@blogger.com (Aaditya)Tue, 19 Jan 2010 05:45:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-23328526023928855812010-01-19T05:45:36.395-08:009Akshit took out a coin of his pocket and said to me, 'Heads I win, Tails I lose. I bet half the money in my pocket.'
He tossed and lost. And the game continued for number of times, each time betting half the money in his pocket. We don't remember how many times the coin was tossed or how long the game went, but he lost exactly the same no. of times as he won the bet.
What do you think, did he, on the whole, gain or lose?<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/YhapILzg15g" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2010/01/heads-i-win-tails-i-lose.htmlNumber of Triangles.http://feedproxy.google.com/~r/Toughnut/~3/_IpmCG6yN_Y/number-of-triangles.htmlnoreply@blogger.com (Aaditya)Sun, 17 Jan 2010 03:34:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-81665498592503292062010-01-17T03:34:54.693-08:009Take a good look at the figure below:
Count the no. of triangles in this figure.
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/_IpmCG6yN_Y" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2010/01/number-of-triangles.htmlThe Cereal Box Surprisehttp://feedproxy.google.com/~r/Toughnut/~3/Vyd9j6VcgPM/cereal-box-surprise.htmlnoreply@blogger.com (Aaditya)Sat, 21 Nov 2009 13:25:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-76827088839885258952009-11-21T13:26:18.136-08:003Suppose a box of cereal costs 5$, and each box has a toy in it. There are 5 different toys for you to collect; by collecting all of them you can assemble them together and create a giant robot. If the toys have equal probabilities of turning up - that is, each toy is 1/5 likely to appear in a randomly chosen cereal box - how much will you have to spend, on average, before you can assemble the giant robot of your dreams?<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/Vyd9j6VcgPM" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/cereal-box-surprise.htmlSplitting Problemhttp://feedproxy.google.com/~r/Toughnut/~3/u2d0mHblgqg/splitting-problem.htmlnoreply@blogger.com (Aaditya)Sat, 21 Nov 2009 13:04:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-22860760783998403722009-11-21T13:07:15.547-08:006How do you cut a rectangular cake into two equal pieces with one straight cut when someone has already removed a rectangular piece from it? (The removed piece can be of any size or any orientation.)
consider these images:
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/u2d0mHblgqg" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/splitting-problem.htmlAn Ant and a Cubehttp://feedproxy.google.com/~r/Toughnut/~3/oWrqyEg-KPo/ant-and-cube.htmlnoreply@blogger.com (Freddo)Fri, 20 Nov 2009 18:47:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-74047378875945149272012-03-20T14:38:50.567-07:005An ant starts eating a 3*3 rubik's cube made up of cheese at a corner(vertex). What is the probability that the last cube it eats is the body-center cube?
The ant can only travel from a cube to the adjacent cubes (i.e. having common faces)
Courtesy: Nitin Basant<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/oWrqyEg-KPo" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/ant-and-cube.htmlMonty Hall problem a.k.a. The 3 door problemhttp://feedproxy.google.com/~r/Toughnut/~3/O2KF8xb0slk/monty-hall-problem-aka-3-door-problem.htmlnoreply@blogger.com (Freddo)Wed, 18 Nov 2009 06:11:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-40697256729272394542009-11-18T07:32:29.281-08:008Although I'm sure most of the ToughNut readers are familiar with this problem but I've met a lot of people with great aptitude who seem to have all sorts of confusion and disagree with the solution. Lets discuss and debate about the conflicting opinions that we all have. Here it goes...
Monty Hall problem
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Suppose you're on a game show and you're given the choice of three doors. Behind one door is a...<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/O2KF8xb0slk" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/monty-hall-problem-aka-3-door-problem.html5 Pirates Puzzlehttp://feedproxy.google.com/~r/Toughnut/~3/Ymhq_34xvU8/5-pirates-puzzle.htmlnoreply@blogger.com (Freddo)Tue, 17 Nov 2009 21:42:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-5559540701029528232009-11-17T21:43:49.741-08:0010Perhaps the most common of all math/logic puzzles being discussed in forums on the internet, yet an interesting one. Here it goes...
There are five rational pirates, A, B, C, D and E. They find 100 gold coins. They must decide how to distribute them.
The Pirates have a strict order of seniority: A is superior to B, who is superior to C, who is superior to D, who is superior to E.
The Pirate world's rules of distribution are thus: that the most senior pirate should propose a distribution...<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/Ymhq_34xvU8" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/5-pirates-puzzle.htmlInformation for puzzle solvers!!http://feedproxy.google.com/~r/Toughnut/~3/j67LNTOAM8c/information-for-puzzle-solvers.htmlnoreply@blogger.com (Freddo)Sun, 15 Nov 2009 19:16:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-54250698617132181282009-11-15T19:17:48.492-08:000Hi puzzlers,
The very idea of ToughNut is to bring in as many challenging and brainteasing puzzles as possible and share them with the followers of this blog. To take the idea a step ahead I invite you all to participate in collaborative publishing. I encourage you to email puzzles directly to itsfreddo.toughnut@blogger.com and have them published on this blog. I would strongly encourage all contributors to mention their names in the end of the email so that they are fairly credited for...<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/j67LNTOAM8c" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/information-for-puzzle-solvers.htmlThe Scared Guards Problemhttp://feedproxy.google.com/~r/Toughnut/~3/GkEePp69dd4/scared-guards-problem.htmlnoreply@blogger.com (Freddo)Sun, 15 Nov 2009 18:59:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-2647405937376325972009-11-15T18:59:01.068-08:003561 security guards are positioned so that no two pairs of guards are the same distance apart. Every guard watches the guard closest to him. Is there an arrangement of the guards so that every guard is being watched?
Source: http://www.cs.rpi.edu/~magdon/miscellaneous/puzzles/puzzles.html
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/GkEePp69dd4" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/scared-guards-problem.html5 cards magic trickhttp://feedproxy.google.com/~r/Toughnut/~3/fBx3iU08Vng/5-cards-magic-trick.htmlnoreply@blogger.com (Freddo)Sun, 15 Nov 2009 18:48:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-46729692005114270172009-11-15T19:00:12.426-08:005Two magicians, John and Hull, perform a trick with a shuffled deck of cards, jokers removed. John asks a member of the audience to select five cards at random from the deck. The audience member passes the five cards to john, who examines them, and hands one back. John then arranges the remaining four cards in some way and places them face down, in a neat pile.
Hull, who has not witnessed these proceedings, then enters the room, looks at the four cards, and determines the...<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/fBx3iU08Vng" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/5-cards-magic-trick.html6 people in a grouphttp://feedproxy.google.com/~r/Toughnut/~3/EuOiAjUszvY/6-people-in-group.htmlnoreply@blogger.com (Freddo)Sat, 14 Nov 2009 15:02:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-49186558317511647492009-11-14T15:25:24.236-08:001 Prove that in a group of six people, there will always be three people that are mutual friends or mutual strangers. (Assume that “friend” is symmetric-if x is a friend of y, then y is a friend of x.)
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/EuOiAjUszvY" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/6-people-in-group.htmlCocktail Partyhttp://feedproxy.google.com/~r/Toughnut/~3/l5hY0gn3gTs/cocktail-party.htmlnoreply@blogger.com (Freddo)Sat, 14 Nov 2009 14:58:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-47959297844321666712009-11-14T15:00:19.775-08:001Prove that in any cocktail party with two or more people, there must be at least two people who have the same number of friends. (Assume that "friend" is symmetric-if x is a friend of y, then y is a friend of x.)
Hint: Use pigeonhole principle
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/l5hY0gn3gTs" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/cocktail-party.htmlBhaddo, Tawar and KT (Tough)http://feedproxy.google.com/~r/Toughnut/~3/QBeJrZAA50w/bhaddo-tawar-and-kt.htmlnoreply@blogger.com (Freddo)Fri, 13 Nov 2009 14:55:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-65580440154984711482009-11-14T02:18:28.653-08:002Mr. Bhaddo choses two different numbers greater than N but less than M & tells their sum to Mr. Tawar and their product to Mr. KT. The following conversation ensues:
Mr. Tawar: I cannot determine the two numbers.
Mr. KT: I cannot determine the two numbers either.Mr. Tawar: I still cannot determine the two numbers.Mr. KT: Now I can determine the two numbers.Mr. Tawar: Now I can determine the two numbers also. ...<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/QBeJrZAA50w" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/bhaddo-tawar-and-kt.html3 Familieshttp://feedproxy.google.com/~r/Toughnut/~3/OFBhW5aK7ok/3-families.htmlnoreply@blogger.com (Freddo)Thu, 12 Nov 2009 13:18:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-16652050294138293402012-03-20T14:39:50.838-07:005Three families make a remarkable discovery. The sum of the ages of their members are all the same, the sum of the squares of the ages of their members are all the same, and the sum of the cubes of the ages of their members are all the same. Everyone in all 3 families has a different age, and nobody is more than 100 years old.
What is the smallest possible sum of their ages? Can this be done with 4 families? <br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/OFBhW5aK7ok" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/3-families.htmlRed-eyed monks and brown-eyed monks on an island?http://feedproxy.google.com/~r/Toughnut/~3/ngM1rAxv_Lo/red-eyed-monks-and-brown-eyed-monks-on.htmlnoreply@blogger.com (Freddo)Thu, 12 Nov 2009 07:59:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-13197687365241935052009-11-12T08:00:19.639-08:004There are 1000 monks living on an island, some with brown eyes and some with red eyes. Monks who have red eyes are cursed, and are supposed to commit suicide at midnight. However, their religion forbids them to know their own eye color, or even to discuss the topic; thus, each monk can (and does) see the eye colors of all other monks, but has no way of discovering their own (there are no reflective surfaces).
All the monks are highly logical and devout, and they all know that each other is...<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/ngM1rAxv_Lo" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/red-eyed-monks-and-brown-eyed-monks-on.htmlExtension of 2 eggs problemhttp://feedproxy.google.com/~r/Toughnut/~3/RJxUlce5ySg/extension-of-2-eggs-problem.htmlnoreply@blogger.com (Freddo)Wed, 11 Nov 2009 08:11:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-40048636789725098072009-11-11T08:11:36.167-08:000How do you solve the problem at the link below for 3 eggs?
http://tough-nut.blogspot.com/2009/11/2-eggs-problem.html
How do you do it for k eggs??<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/RJxUlce5ySg" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/extension-of-2-eggs-problem.htmlB'day twins problemhttp://feedproxy.google.com/~r/Toughnut/~3/WrRvVQlGt-M/bday-twins-problem.htmlnoreply@blogger.com (Freddo)Wed, 11 Nov 2009 06:02:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-85165264630259619822009-11-11T06:02:25.563-08:006Sheila and He-Man are twins; Sheila is the OLDER twin. Assume they were born immediately after each other, an infinitesimally small - but nonzero - amount of time apart. During one year in the course of their lives, Sheila celebrates her birthday two days AFTER He-Man does. How is this possible? Bonus: What is the maximum amount of time by which Sheila and He-Man can be apart in their birthday celebrations during the same year? Note: For both Sheila and He-Man, these birthday celebrations...<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/WrRvVQlGt-M" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/bday-twins-problem.htmlGlobe Traversal Problemhttp://feedproxy.google.com/~r/Toughnut/~3/9fQe33f6To4/globe-traversal-problem.htmlnoreply@blogger.com (Freddo)Wed, 11 Nov 2009 05:54:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-88607952380698787602009-11-11T05:55:14.339-08:001how many places are there on the earth that one could walk one mile south, then one mile west, then one mile north and end up in the same spot? to be precise, let's assume the earth is a solid smooth sphere, so oceans and mountains and other such things do not exist. you can start at any point on the sphere. also, the rotation of the earth has nothing to do with the solution; you can assume you're walking on a static sphere if that makes the problem less complicated to you.<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/9fQe33f6To4" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/globe-traversal-problem.htmlFive selfish women, a monkey, and some coconuts (2 star)http://feedproxy.google.com/~r/Toughnut/~3/GXomFmO1A3g/five-women-monkey-and-some-coconuts-2.htmlnoreply@blogger.com (Aaditya)Tue, 10 Nov 2009 10:19:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-21697868588656354162009-11-10T10:25:51.044-08:003Five women crash-land their airplane on a deserted island in the South Pacific. On their first day they gather as many coconuts as they can find into one big pile. They decide that, since it is getting dark, they will wait until the next day to divide the coconuts.
That night each woman took a turn watching for rescue searchers while the others slept. The first watcher got bored so she decided to divide the coconuts into five equal piles. When she did this, she found she had one remaining...<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/GXomFmO1A3g" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/five-women-monkey-and-some-coconuts-2.htmlBulbs-Switches matching problemhttp://feedproxy.google.com/~r/Toughnut/~3/UkrxAgSbZEI/bulbs-switch-matching-problem.htmlnoreply@blogger.com (Freddo)Tue, 10 Nov 2009 07:09:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-69884203277189954522009-11-10T07:39:08.327-08:002There are 1000 bulbs in a room & the switches for these are in another room arranged in a random fashion.You have to find an optimum strategy to match the bulbs to corresponding switches so that the number of times u enter into the room to look at the bulbs is minimum.
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/UkrxAgSbZEI" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/bulbs-switch-matching-problem.html25 cards in a dark roomhttp://feedproxy.google.com/~r/Toughnut/~3/FmbIovGb8jQ/25-cards-in-dark-room.htmlnoreply@blogger.com (Freddo)Tue, 10 Nov 2009 03:43:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-85377007929942630622009-11-10T03:43:38.529-08:004A deck of 25 cards, 14 of which are facing up & 11 are facing down, is lying on a table in a dark room. You are asked to go in that room and split the deck into two such that total number of cards facing up in each deck are equal. How do you do that?<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/FmbIovGb8jQ" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/25-cards-in-dark-room.html2 eggs problemhttp://feedproxy.google.com/~r/Toughnut/~3/F-i5jWBSalU/2-eggs-problem.htmlnoreply@blogger.com (Freddo)Tue, 10 Nov 2009 03:34:00 PSTtag:blogger.com,1999:blog-7167710173717429664.post-67707318043466731532009-11-10T03:34:59.008-08:0012* You are given 2 eggs.
* You have access to a 100-storey building.
* Eggs can be very hard or very fragile means it may break if dropped from the first floor or may not even break if dropped from 100 th floor.Both eggs are identical.
* You need to figure out the highest floor of a 100-storey building an egg can be dropped without breaking.
* Now the question is how many drops you need to make. You are allowed to break 2 eggs in the process<br/>
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[[ This is a content summary only. Visit my website for full links, other content, and more! ]]<img src="http://feeds.feedburner.com/~r/Toughnut/~4/F-i5jWBSalU" height="1" width="1" alt=""/>http://tough-nut.blogspot.com/2009/11/2-eggs-problem.html