humour

A smart guy approaches a dumb guy and says:
- We'll ask each other questions and for each question you answer incorrectly you will give me a dollar. For each question I answer incorrectly I will give you 10 dollars because I am smart.
-uh.. OK...
-Great. What's the capital of Brazil?
-uh I don't know, here's a dollar
-How many colours are in a rainbow?
-uh I don't know, here's a dollar
-When was the battle of Waterloo fought?
-uh I don't know, here's a dollar
-OK, now it's your turn to ask a question...
-uh OK...what is green...flies...and is smoking?
-(thinks foor a bit) I don't know! Here's 10 dollars but tell me the answer.
-uh I don't know, here's a dollar...