Fun Riddles

Question: An empty bus pulls up to a stop and 10 people get on. At the next stop 5 people get off and twice as many people get on as at the first stop. At the third stop 25 get off.

How many people are on the bus at this point?

Question: How can forty elephants have forty-fore heads?

Question: I am the only organ that named myself.What am I?

Question: When do you go at red, but stop at green?

Question: 100 feet in the air, yet its back is on the ground.

What is it?