Riddle me this
Borrowed a book from a fellow colleague who majored in philosophy. Really nice book with lots of puzzles.
1. What is the temperature when it's twice as cold as zero degrees?
2. Three friends are hiking to a remote destination in a wilderness area. The hike takes 6 days. Each person can carry only enough food and water for 4 days. Without sacrificing anyone or endangering anyone's life, the goal is to get as many people as possible to the destination. How many people can safely get to their destinination?
3. In a box you have 13 white marbles and 15 black marbles. You also have 28 black marbles outside the box. Remove 2 marbles, randomly, from the boz. If the marbles are of different colors, put the white one back in the box. If they are of the same color, remove both of them and replace them with a black marble from outside the box. Continue this process until onle one marble remains in the box. What color is the last marble?
4. Why are manhole covers circular?
Haha...have fun trying!
1. What is the temperature when it's twice as cold as zero degrees?
2. Three friends are hiking to a remote destination in a wilderness area. The hike takes 6 days. Each person can carry only enough food and water for 4 days. Without sacrificing anyone or endangering anyone's life, the goal is to get as many people as possible to the destination. How many people can safely get to their destinination?
3. In a box you have 13 white marbles and 15 black marbles. You also have 28 black marbles outside the box. Remove 2 marbles, randomly, from the boz. If the marbles are of different colors, put the white one back in the box. If they are of the same color, remove both of them and replace them with a black marble from outside the box. Continue this process until onle one marble remains in the box. What color is the last marble?
4. Why are manhole covers circular?
Haha...have fun trying!
posted by samuel lee at
11:53 PM
3 Comments:
Hi Samuel, here are my feeble attempts are your questions:
1. Twice as cold as zero degrees. Are you talking about the Kelvin scale or the Celsius/Fahrenheit scale? For the former (which I assume is the one used), you cannot define something that is twice as cold as zero degrees as it will still be zero. 2 times 0 is still 0.
2. One friend will have to leave them after two days and give the remaining two days' worth of provisions to his friends. Then each friend will have 3 days worth. The next day, the second guy will leave, and give the remain 2 days worth to the last man, hence leaving him with 4 days worth. At most one can make it to the destination.
Of course, they should just stay at home because I don't think there is enough for them to make it back alive.
3. There will also be an odd number of white marbles in the box so it has to be a white one left in the end.
4. Manhole covers are circular so that we can always cover it in any orientation and they can never fall into the hole from above.
By
Tsk, at Sunday, February 04, 2007 1:27:00 AM
1. Having been in sub-zero temperatures, it is definitely possible to feel like you are in a climate twice as cold as freezing. A wild stab would be -25 degrees, assuming the perception of variance in temperature is linear and room temp is +25 degrees.
2. Two - one of them will have to give up on the trip and split the supplies so the remaining two have 6 days' worth. (The question only asks for the destination, so the return trip isn't taken into consideration.)
3. White; the white marbles can only be removed 2 at a time, leaving the only possible scenario of 1 white 1 black at the penultimate step, then just the white.
4. Ditto Barney's answer - in addition, the heavy buggers are easier to move (ie. roll) around. According to friends who had first-hand experience, this was a popular interview question at Microsoft and IBM.
- random passerby :)
By
Meow, at Tuesday, February 06, 2007 2:15:00 PM
Barney and meow got all 4 correct! haha... really smart :)
1) we are talking abt Kelvin. twice as cold as O degree celsius = half of 273 kelvin = 136.5 kelvin
2) both answered correctly
3) both answered correctly
4) both answered correctly
And meow is right! The book where the questions are taken from is ," How to ace in mind boggling interviews." and true, microsoft uses such questions :)
By
samuel lee, at Thursday, February 08, 2007 10:28:00 PM
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