Saturday, February 18, 2017

The Collapsing Bridge

The bridge will collapse in 17 minutes! Four people need to cross the bridge before it collapses. It is a dark night and they have only one flashlight among them.

Only two people can cross at a time.
  • Alice takes one minute to cross.
  • Bob takes two minutes.
  • Carol takes five minutes
  • Dave takes 10 minutes to cross.
How can they all get across before the bridge collapses? Click below to see the answer.


Anonymous said...

What does the flashlight have to do with anything? I'm assuming any party cannot cross without the flashlight?

Bill the Lizard said...

Yes, because it's dark, you can't cross the bridge without the flashlight.