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U2 has a concert that starts in 17 minutes and they all must cross a bridge to get there. All 4 men begin on the same side of the bridge. You must help them develop a plan to cross to the other side. It’s night. There’s one flashlight.

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U2 has a concert that starts in 17 minutes and they all must cross a bridge to get there. All 4 men begin on the same side of the bridge. You must help them develop a plan to cross to the other side. It’s night. There’s one flashlight.

A maximum of 2 people can cross at one time.

Any party that 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.

The rates are as follows:

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 returns with the flashlight, a total of 20 minutes has elapsed and you’ve failed the mission.

NOTE: There is no trick behind this. It is a simple movement of resources in the appropriate order. There are two known answers to this problem.

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Bono

1 Minute

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Edge

2 Minutes

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Adam

5 Minutes

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Larry