Those of you who loved arguing about the Monty Hall problem might enjoy this one.

This one was tested in one of the episodes of Mythbusters. I don't know where they heard of the problem, but I assume it had been in circulation earlier.

Suppose you have an airplane ready to take off, but instead of standing on an ordinary airport runway, suppose it is standing on a monster conveyor belt. Suppose the airplane is headed west. At first, both the airplane and the conveyor belt are motionless. Then the pilot revs up the engine, such that the airplane would normally begin moving west. At the same moment, the conveyor belt begins moving the opposite direction. The conveyor belt accelerates at the same rate as the normal acceleration of the airplane, such that, for instance, by the time the airplane would normally be moving westward at 50 mph, the surface of the conveyor belt is moving eastward at 50 mph, and so on.

So the question is: would the airplane be able to take off, or not?

Unlike the Monty Hall problem, this is not "pure" logic, but it requires some rudimentary knowledge of how airplanes work. If you lack that knowledge, I suppose someone will supply it as soon as you have shown your ignorance by guessing wrong!

I know this problem has been discussed and argued about at great length in the forum pages of the Mythbusters website. I would have posted a link, but I can't get through to the forum right now.