Logic Riddles

Question: A man wants to buy a used car. He finds a beautiful Buick for $9500, but he buys it without paying a dime.

How did he manage this?

Question: If a white house is white and a yellow house is yellow, what color is a green house?

Question: You have lost your mother at the carnival. You search for her and eventually you see her.

What's the first thing you do when you see her?

Question: A person was born in 1940. Today is his 18th birthday.

How is that possible?

Question: There are 31 horses on a cliff, first they jump into the air, then they come down and stop, then they stand still.

Why do they do this?