A professor sits with a farmer in a train.
Bored, the professor says to the farmer:
“I ask you a question, if you can’t answer it, you give me $5; then you ask me a question, if I can’t answer it, I give you $500, what do you think?”
The farmer nods.
The professor asks the farmer:
“What is the distance between the Earth and the Moon?”
The farmer silently takes out $5 and give it to the professor.
The farmer asks the professor:
“What animal has three legs when ascending a mountain and four legs when descending a mountain?”
The professor thinks hardly but couldn’t find an answer, so he reluctantly pulls out $500 for the farmer.
The farmer takes the $500 and prepares to nap, the professor asks:
“What animal is it!?”
The farmer takes out $5 and give it to the professor, then he falls asleep.