Thursday, April 28, 2005
A quick, throw-away puzzle.
Rumour has it that the following puzzle is used by at least one company during job interviews to test an applicant's critical thinking skills. Through exhaustive search, it's pretty easy to find the solution, but it's a bit more challenging to analyze the puzzle to zero in on the solution based on pure logical deduction. So, we're not just after the solution, we're after how you got to it. (By the way, apparently job applicants are given only five minutes to solve it, which is why the logical deduction thing is not a bad idea.)
"U2" has a concert that starts in 17 minutes and the group members must all cross a bridge to get there. All four men begin on the same side of the bridge. You must help them across to the other side. It is night. There is one flashlight. A maximum of two people can cross at one time. Any party who crosses, either one or two people, must have the flashlight to see. The flashlight must be walked back and forth, it cannot be thrown, etc. Each band member walks at a different speed. A pair must walk together at the rate of the slower man's pace, based on this information:
* Bono: - 1 minute to cross
* Edge: - 2 minutes to cross
* Adam: - 5 minutes to cross
* Larry: - 10 minutes to cross
For example: if Bono and Larry walk across first, 10 minutes have elapsed when they get to the other side of the bridge. If Larry then returns with the flashlight, a total of 20 minutes will have passed and you will have failed.
And ... go. Tick, tick, tick ...
OPEN FOR SOLUTIONS, noon Eastern time, Friday, Apr 29, so don't post any answers yet.