The mathematician accepted the challenge and they switched places for the next speech
A Nobel Prize winning mathematician was traveling from one university to the other as a guest speaker. He was traveling by a hired limousine. After several sessions and being on the road the whole day, the mathematician and his driver stopped for dinner.
Suddenly, while eating, the driver said, "I have heard your speech so many times that I think I could deliver the speech word-for-word."
The mathematician accepted the challenge and they switched places for the next speech. As planned, the driver dressed like the professor and the professor dressed as the driver and sat at the back of the auditorium.
The driver delivered the speech flawlessly and opened up the floor for question, usually there were none. But one of the students at the university with a very large ego decided to embarrass the Nobel laureate.
After the student asked his question for ten straight minutes the driver laughed and answered, "That question is so simple that I will let my driver in the back answer it."