A prisoner is standing with two prison officers in the execution chamber. He must choose one of two chairs and sit in it. One chair is an electrified chair that kills instantly. The other chair is harmless.

The prisoner is allowed to ask one question from either one of the officers. One officer always tells the truth and the other always lies but the prisoner does not know who tells the truth or who tells lies.

What question can the prisoner ask and determine which chair is the harmless chair?

Ask either prison officer this question, "If I were to ask the other officer which chair is harmless, which chair would he show me?"

Is the chair the prison officer indicates the harmless chair? You have to figure this out.