Brain Teasers
'U2'
`U2` has a concert that starts in 17 minutes and they 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 1 or 2 people, must have the flashlight with them. 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:
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 have passed and you have failed the mission. Your goal is to get all the men across in 17 mins or less.
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 have passed and you have failed the mission. Your goal is to get all the men across in 17 mins or less.
Answer
Bono(1min) and Edge(2min) walk across first bringing the total to 2 minutes. Then Bono(1) walks the flashlight back, totaling 3 minutes. Adam(5)and Larry(10) walk across, totaling 13 minutes. Edge(2) walks the light back, totaling 15 minutes. Edge(2) and Bono(1) walk across, totaling the answer, 17 minutes.Hide Answer Show Answer
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Comments
I was asked this question in an interview once!
So Edge can actually walk it back the first time too then. Huh, good puzzle.
Yeah, but I saw this on another web site yesterday.
I've seen this one before, but it's still a good one!
One of the combinations I didn't think of, very good.
FYI : I heard this teaser is one of the questions that potential microsoft employees are asked and that misrosoft expects u to answer it in five minutes or less.
I really liked this one
Yup I heard the Microsoft thing too...
It's always a good one I also have found more ways
well i was thinking that they must have carried one person on their backs, like piggyback!!
good teaser, thanks
good teaser, thanks
It's like the old wolf, goat, bag of corn, and farmer riddle...cept with a few added variables....
i got this in a little under 3 minutes.
i got this in a little under 3 minutes.
why u2 did u really need to use a band? o well i loved it
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