Simple Question?

·     One day during a speaking tour, Albert Einstein's driver, who often sat at the back of the hall during his lectures, remarked that he could probably give the lecture himself, having heard it so many times. Sure enough, at the next stop on the tour, Einstein and the driver switched places, with Einstein sitting at the back in his driver's uniform.

Having delivered a flawless lecture, the driver was asked a difficult question by a member of the audience. "Well, the answer to that question is quite simple," he casually replied. "I bet my driver, sitting up at the back there, could answer it..."