This problem was published in MAA on line: Crossing a Rickety Bridge at Night By Flashlight.
- 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:
- Annie crosses the bridge in 1 minute,
- Bob crosses the bridge in 2 minutes,
- Volodia Mitlin crosses the bridge in 5 minutes,
- Dorothy crosses the bridge in 10 minutes.