U2 walks the bridge

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 cross 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

Solution

Bono and Edge go to destination. 2 minutes. 15 minutes remaining.

Bono goes back to source. 1 minute. 14 minutes remaining.

Bono hands Larry the torch (Larry is the most qualified to hold the torch, even if he is a slow coach).

Adam and Larry go to destination. Takes 10 minutes. 4 minutes remaining.

Larry hands Edge the torch and he (Edge) walks back to source. Takes 2 minutes, 2 minutes remaining.

Bono and Edge go to destination. Takes 2 minutes. Problem solved.

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