Four people need to cross a rickety bridge at night. They have one flashlight and the bridge is too dangerous to cross without it. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins, and 10 mins. What is the shortest time needed for all four to cross the bridge?
Answer
17 minutes (1 & 2 cross, 1 returns, 7 & 10 cross, 2 returns, 1 & 2 cross)