Kids Riddles

Question: You are in a car with some helium balloons and hit the gas. While you accelerate, which way does the balloon move?

Question: I give advice to others,
yet I know nothing myself.
I am a hitchhiker destined to stay still.

Question: Filled with garb,
the price is free.
Just return what you don't need.

What am I?

Question: Paul is 20 years old in 1980, but only 15 years old in 1985.How is this possible?

Question: There was once three trees. The first tree did whatever the third tree did, and the third tree did what ever the second one does. What happens if tree number two gets cut down?