Tease me with jokes.

One day, a girl said to a scientist, "Let me ask you a question. If you can answer, I will give you 5 yuan money. If you can't answer, just give me 50 yuan, okay? " The scientist pondered for a while and said, "All right, you go." The girl said, "There is an animal with five heads and eight hands. what did you say ? I'll give you five days to think about it. " Scientists searched more than n kinds of materials in these five days, but found nothing. So the scientist asked the girl, "What are you talking about?" The girl said, "You don't know that you are going to give me 50 yuan. I don't understand. I'll give you 5 yuan, and you have to give me 45 yuan! " The scientist fainted on the spot.