There are 8 people that need to cross a river. The water is too deep and fast to walk or swim across, and the only transportation device available is a raft. The raft can only be operated by adults, cannot float across the river on its own, and can carry at most two people.

The 8 people are a juvenile delinquent, her jailer, and a dysfunctional family of six: mother, father, two sons, and two daughters. To be clear, the only adults are the jailer, the mother, and the father.

Unfortunately some people fight with each other:

The juvenile delinquent will fight with anybody if her jailer is not present.

The father fights with either daughter if the mother is not present to mediate.

The mother fights with either son if the father is not present to mediate.

How can these 8 people cross the river without any fights? How many trips on the raft did it take?

For a fun way to test out your theories, click here and then click on the blue circle.

This really wasn't that hard. The simplest way to do this is to use the link that's provided to act the problem out while you're working on it.

 

The solution is as follows...

 

The jailer brings the juvenile delinquent to the opposite side, then returns. The jailer then brings over one of the daughters and returns with the delinquent. The mother brings over the second daughter, then returns. The mother and the father go over, then the father returns. The jailer and the juvenile delinquent go to the opposite side and the mother goes back. The mother and the father float over, then the father returns for the first son. The jailer and the juvenile delinquent go over once again so that the jailer can bring the second son to his parents. The jailer then returns for her juvenile delinquent.

Here's a chart that could help explain it a little better.

(goes over ---> comes back)
jailer & juvenile delinquent ---> jailer
jailer & daughter 1 --- > jailer & juvenile delinquent
mother & daughter 2 ---> mother
mother & father ---> father
jailer & juvenile delinquent ---> mother
mother & father ---> father
father & son 1 ---> jailer & juvenile delinquent
jailer & son 2 ---> jailer
jailer & juvenile delinquent ---> problem solved

I'm sure I could have explained that better, but it works.

Posted by Kristi on 2005-09-26 19:39:29