Tuesday, September 18, 2007

Crossing the bridge

A group of four people has to cross a bridge. It is dark, and they have to light the path with a flashlight. No more than two people can cross the bridge simultaneously, and the group has only one flashlight. It takes different time for the people in the group to cross the bridge:

Antonioni crosses the bridge in 1 minute,
Bergman crosses the bridge in 2 minutes,
Chaplin crosses the bridge in 5 minutes,
Dovzhenko crosses the bridge in 10 minutes.

How can the group cross the bridge in 17 minutes?

1 comment:

Taposik said...

1) A + B cross
2) A comes back
3) C + D cross
4) B comes back
5) A + B cross