Crossing the Bridge

Four people are on one side of a bridge that they need to cross. It is dark, there are holes in the bridge surface, and they only have one flashlight which must travel with them as they cross. To add to their troubles, the bridge will only support two people at a time.

* Now person #1 can walk cross in 1 minute.
* Person #2 has a limp and can cross in 2 minutes.
* Person #3 has a sprained ankle can cross in 5 minutes.
* Person #4 has a cast on his leg and takes 10 minutes to cross.

No matter how fast a person can cross, he must wait for his companion. If #1 goes with #2, it takes 2 minutes for them to cross.If number #2 goes with #4,it takes them 10 minutes.The flashlight cannot be thrown, instead it must be carried and delivered from person to person. The 4 people are trying to make it across in the fastest possible time to make an important appointment in the next town.

What is the fastest time in minutes for them to cross the bridge?


Answers:

Trip 1: Person 1 & Person 2 across = 2 min
Trip 2: Person 2 back = 2 min
Trip 3: Person 10 &Person 5 across = 10 min
Trip 4: Person 1 back = 1 min
Trip 5: Person 1 w/ Person 2 = 2 min.
Total 17 minutes.