A blonde and a college professor are sitting next to each other on a plane. As the trip is long, the professor asks her if she'd like to play a fun game to help spend the time. The blonde declines, arguing she's going to spend her time napping. She leans back in her seat and closes her eyes.
The professor, however, insists: But it's a very funny game! Here, let me explain it to you. I ask you a question and, if you don't know the correct answer, you have to give me 5 dollars and vice-versa. The blonde refuses to play, which aggravates the man. Fine! What if you gave 5 dollars for each question you don't know the answer to, while I'll give you 500 for every question I don't know the answer to? What do you say to that?
This offer, heaven knows why, seems to arouse the blonde's attention, who reluctantly agrees to play.
The professor's first question is: What is the distance between the Earth and the Moon? Without a word, and before wasting any time, the blonde opens her wallet and hands the professor a five dollar bill. Next, she asks him a question: What has four legs before climbing up a mountain and only three after climbing it down?
The professor is speechless for a moment. Straight away, he starts his computer and searches the Internet, while also e-mailing a few of his peers, asking for help. He also makes a couple of phonecalls. Meanwhile, the blonde falls asleep.
After almost an hour's worth of suffering and despair, unable to obtain an answer, he wakes the blonde up and hands her a five hundred dollar bank note. She accepts and falls back asleep. Enraged, the professor wakes her up again and shouts: Wait a minute! This isn't over... What's the answer? Apparently drowsy and without uttering a word, the blonde opens her wallet again and takes out another five dollar bill which she hands over to the professor. She reclines back in her chair and falls back asleep.