At a televised quiz show, the contestant who is standing on a platform is told to choose between two elevator doors facing him. One of the doors would lead to a wonderful prize, the other to an onerous task.
In front of each elevator door was placed a uniformed sentinel, a person selected from the audience of the quiz show.
One of the sentinels was required to only lie, and the person selected said he was a politician so this would not be much of a problem for him. The sentinels were informed of what the elevator doors led to.
The other sentinel was required to only tell the truth, and as he was a mathematician this would not be a difficult problem for him, he said.
The contestant was informed that one of the sentinels would certainly lie and the other would certainly tell the truth.
The contestant was required to direct just one question to one of the sentinels for the purpose of selecting the elevator door with the prize.
What was the winning question?