In the puzzle Four people on a Bridge we met four people who needed to cross a bridge at night. In this puzzle, there are five people who must cross two sequential bridges at night. As in the original puzzle, there are some hindrances:

The bridges can only support two people crossing at a time.

Each person has a different speed in which they can cross: 10 minutes, 7 minutes, 5 minutes, 2 minutes, and 1 minute.

They have only two flashlights to share among them.

What is the shortest amount of time it will take for all five people to cross both bridges?

(In reply to 3 less by MathManiac)

The flashlight only illuminates a small portion of the bridge. When two people use a flashlight, they have to stay together, moving at the speed of the slower person. 1 & 2 cannot race "between the cracks" of 7&10's crossing.

Posted by TomM on 2005-06-25 21:29:30