The Puzzle Page
by: Erik Oosterwal
Crossing the Bridge
Here's a puzzle I found in an online book dedicated as a salute to Martin
Gardner, everybody's favorite puzzle master. In the chapter,
Puzzles from Around the World, Richard I. Hess provides this
little stickler. It's a bit tricky at first but you should find that insight
will strike you after some thinking.
Four men approach a bridge at night. The bridge is old and rickety
and can support, at most, two men going across at one time. They have
only one flashlight to share between them. Each man has differing abilities
and some take more time to cross than the others. The times it takes
for each man to cross are: 1 minute, 2 minutes, 5 minutes, and 10 minutes.
When crossing in pairs, they can only cross as fast as the slowest
man can go. How can all four men cross in only 17 minutes total?
I give up, show me the Answer
All original puzzles and solutions are © Erik Oosterwal 1993-2008
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