Brain Boggler


given by

Krzysztof Chris Ciesielski

April 20, 1999

Imagine that somewhere deep in West Virginia countryside there is a T-shape crossroad with roads going to Richmond, Morgantown, and Charleston, respectively. At the crossroad live two brothers, identical twins. Both always answer all questions perfectly precise, but one always tells the truth, the other always lie.

Driving from Richmond, and being in a hurry for this lecture, you approach to the crossroad and you realize that you do not know which way is to Morgantown. Luckily, one of the twins comes out from the house ready to help you. But which one it is? You do not know and you have a time to ask just one question, with an answer YES or NO, to find how to get to Morgantown on time.

What question should you ask?

For an answer click here.

Last modified April 19, 1999.