A guy asked a girl in a university library: "Do you mind if I sit beside you?"

The girl replied with a loud voice:
"NO WAY....I DON 'T WANT TO SLEEP WITH YOU!"

All the students in the library started staring at the guy. He was truly embarrassed.

After a couple of minutes, the girl walked quietly to the guy 's table and said:
"I study Psychology, and I know what men are thinking. I guess you felt embarrassed, right?

The guy then responded with a loud voice:
"$500 FOR ONE NIGHT? THAT 'S WAAAAY TOO MUCH FOR YOU! "

All the people in the library looked at the girl in shock. The guy whispered back:
"I'm in Political Science, and learning how to screw people"