Question

Tanenbaum, page 156. #2 A missionary lost in Southern California stops at a fork in the road. He knows that two motorcycle gangs inhabit the area, one of which always tells the truth and one of which always lies. He wants to know which road leads to Disneyland. What question should he ask a gang member? Note that he does not know which gang the gang member belongs to.

Answer 1

Answer -

As it is mentioned in the question that there are two motorcycle gang in the area and one of them always tells truth and the other always tell lies. The missionary also does not know which gang tells the truth and which do not. So, there are two possibility that could happen :

1. The missionary can ask both the gangs if the road goes to the disneyland but there would be a confusion because one of the gang is ought to be lying than the other so he would get one yes and one no.
2. Sam goes if he would ask the question indirectly as if the road does not go to the disneyland then also he would get one yes and one no which will again create the confusion.

So, to ask a question which will solve the problem without creating the confusion would be :

• So, the missionary should actually ask both the gangs about what would be answer of the other gang for the question that if the road goes to the disneyland or not and in this way he would get either a yes or a no from both the gangs.

So, we get the correct answer by taking technique with both the gangs.