Four Men & a Bridge

A four-man band 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. Your mission is to direct them so as to get all four across the bridge in 17 minutes or less. It is dark and they have only one flashlight. A maximum of two people can cross at one time. Any party, whether of one or two people, must have the flashlight to get across the bridge. The flashlight must be walked back and forth, it cannot be thrown or conveyed across any other way. Each band member walks at a different speed. A pair must walk together at the rate of the slower man's pace:

• Bono: - can cross in 1 minute
• Edge: - can cross in 2 minutes
• Adam: - can cross in 5 minutes
• Larry: - can cross in 10 minutes

For example: if Bono and Larry walk across first, 10 minutes will 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 the mission.

Notes: There are no tricks to this. It is the simple movement of resources in the appropriate order. Rumor has it that there are two known solutions.

One solution...