Comments for My Tech Interviews

Comment on Challenge – Equal Probability between 1 and 7 by Doggie

Doggie — Sat, 18 Jun 2011 13:07:27 +0000

@navz

You are right it generating all the numbers but there are NOT the same probability of occurring

Calculate the chance of each of the values happening and see.

Comment on How Strong is an Egg? by Doggie

Doggie — Sat, 18 Jun 2011 12:55:17 +0000

@DPT Binary search won’t work since you only have 2 eggs. What happens once the eggs break in the first two steps, you won’t have any more eggs to try for the remaining 5 steps.

Comment on Clock Hands by Doggie

Doggie — Sat, 18 Jun 2011 12:54:19 +0000

@John It is not 23. You have think of it as 2 sets of 12 hours. If it is 12 hours, you logic is fine. You will get 12 – 1 (since it will 12am and 12pm will be the same). Now if you extend it to 2 set of 12 hours. Then you get 11*2=22. If this doesn’t convince you, try writing down all the matchs.

Comment on How Strong is an Egg? by Henry J Law

Henry J Law — Sat, 18 Jun 2011 08:45:00 +0000

Actually, I get the same solution as the updated solution above. But the actual should be 15, as you always needs one more try (actually breaking the egg) in order to confirm that’s the highest floor you can go. In another words, you can never determine the highest floor with a single try (except floor 100, which we won’t start there).

Comment on How Strong is an Egg? by DPTs

DPTs — Fri, 17 Jun 2011 16:34:29 +0000

the first thing that came to mind was binary search! that makes it 7

Comment on Clock Hands by John

John — Thu, 16 Jun 2011 14:44:11 +0000

The error in the answer of 23 is that you are accounting for 12 O clock three times in the day, instead of just twice. In a true day, it should only be accounted for in the very first overlap at 12am. The next time 12am (not 12pm) occurs, it is the next day, and thus does not count.

Comment on How Old Are My Children? by kevin

kevin — Thu, 16 Jun 2011 04:40:13 +0000

we cannot say that a person starts learning piano lessons only at the age of 8. It might also be 7 or 10 or even 12.

Are we supposed to read the mind of Bill…?? LOL…..

Comment on How Old Are My Children? by kevin

kevin — Thu, 16 Jun 2011 04:28:08 +0000

This is really a stupid question! Any one combination of the following is possible…

2, 4, 9 – sum(2, 4, 9) = 15
2, 3, 12 – sum(2, 3, 12) = 17
3, 4, 6 – sum(3, 4, 6) = 13
3, 3, 8 – sum(3, 3, 8 ) = 14
1, 8, 9 – sum(1,8,9) = 18
1, 6, 12 – sum(1, 6, 12) = 19

OK…we can eliminate this 5th answer since both the elder kids are nearly of the same age…. However, you cannot pick up anything as the correct answer since all of them suit…..

The question must be a wrong one.

Comment on Boys and Girls by kevin

kevin — Thu, 16 Jun 2011 03:46:09 +0000

I totally agree with JEO!!! Why do you go for mathematical calculations for simple questions?

The probably must be 2(boys) : 1(girls)……..
consider 2 families.. Since probably of getting a boy and a girl is equal, we can say that one family gets a boy and the other gets a girl. But, since the second family has only a girl, it gets another boy.

Now there are TWO BOYS AND ONE GIRL. Hence the probability must be 2:1 and not 1:1.

Any objections to this?

Comment on How Strong is an Egg? by Zubair Dhalla

Zubair Dhalla — Wed, 15 Jun 2011 19:14:13 +0000

Fools! The answer is 2.
You go to a random floor, number x, and drop the first egg. It survives. You go to floor x+1 and it breaks. Floor x is the maximum height. This is the absolute minimum and relies on pure luck.

Plus you only have 2 eggs.