Good Riddles

Question: A man in a wheelchair is being pushed across a hallway by his wife. When they get to the end of the hallway the man says: stop pushing me. His wife asks why, and the man gets up and starts walking. How did the man get up and start walking if he was in a wheelchair?

Question: A man wants to start a forest fire.There are 80 trees and you have a lighter. How many trees should he burn?

Question: I fasten to walk,
and unfasten to stop.

What am I?

Question: A son's age is the age of his dad's age's digits added together. The son is not nine or older. The dad is of legal age. The dad's age doesn’t end in a zero, and is more than twenty, but less than twenty-five. How old is the dad, and how old is the son?

Question: I died a death that no one has ever died and my grave is in every grocery store.