Tech Interview
A site for technical interview questions, brain teasers, puzzles, quizzles (whatever the heck those are) and other things that make you think!
Category: regular
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Salaries
Posted at 10:51 am , on April 2, 2010
Three coworkers would like to know their average salary. how can they do it, without disclosing their own salaries?
Solution
How about: Person A writes a number that is her salary plus a random amount (AS + AR) and hands it to B, without showing C. B then adds his salary plus a random amount (BS + BR) and passes to C (at each step, they write on a new paper and don’t show the 3rd person). C adds CS + CR and passes to A. Now A subtracts her random number (AR), passes to B. B and C each subtract their random number and pass. After C is done, he shows the result and they divide by 3.
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World Series
Posted at 10:48 am , on April 2, 2010
You have $10,000 dollars to place a double-or-nothing bet on the Yankees in the World Series (max 7 games, series is over once a team wins 4 games).
Unfortunately, you can only bet on each individual game, not the series as a whole. how much should you bet on each game, so that, if the yanks win the whole series, you expect to get 20k, and if they lose, you expect 0?
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100 Factorial
Posted at 8:42 am , on April 2, 2010
how many trailing zeroes are there in 100! (100 factorial)?
Solution
One per factor of 10, and one per factor of 5 (there are more than enough 2’s to pair with the 5’s), plus one per factor of ten squared (one occurrence) and one per factor of 5 squared (three occurrences).
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Oil Mogul
Posted at 8:39 am , on April 2, 2010
You are an oil mogul considering the purchase of drilling rights to an as yet unexplored tract of land.
The well’s expected value to its current owners is uniformly distributed over [$1..$100]. (i.e., a 1% chance it’s worth each value b/w $1..$100, inclusive).
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Vienna
Posted at 8:36 am , on April 2, 2010
It’s the middle ages, you’re travelling across europe and you want to find the way to vienna. you come to a crossroads, now there are two ways to go. at the crossroads stand a knight and a knave. the knight answers every question truthfully. the knave answers every question falsely. you don’t know which guy is which. how can you figure out which road leads to Vienna by only asking one question?
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Duel
Posted at 8:33 am , on April 2, 2010
You find yourself in a duel with two other gunmen. you shoot with 33% accuracy, and the other two shoot with 100% and 50% accuracy, respectively. the rules of the duel are one shot per-person per-round. the shooting order is from worst shooter to best shooter, so you go first, the 50% guy goes second, and the 100% guy goes third.
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Hen
Posted at 8:28 am , on April 2, 2010
If a hen and a half lay an egg and a half in a day and a half, how many hens does it take to lay six eggs in six days?
Solution
If 1.5 hens lay 1.5 eggs in 1.5 days (or 36 hours) then: 1 hen lays 1 egg in 1,5 days or 4 eggs in six days thus 1.5 hens lay 6 eggs in 6 days
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Box ‘o Numbers
Posted at 12:20 pm , on April 1, 2010
Arrange the numbers 1 to 8 in the grid below such that adjacent numbers are not in adjacent boxes (horizontally, vertically, or diagonally):
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| 1 |
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| 6 | 4 | 3 |
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| 2 | 7 | 5 |
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| 8 |
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Coin Problem
Posted at 12:14 pm , on April 1, 2010
some of you may have easily solved the pill weighing problem posed here. If so, you are going to love this problem. It is similar but much more difficult.
from my buddy Tom:
Ok, here’s a tough one (i thought). There are no “aha!” tricks – it requires straightforward deductive-reasoning.
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Parallel Lines
Posted at 10:53 am , on April 1, 2010
Solution
Not really much to solve 🙂
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