Answer:
What can you put in a barrel to make it lighter?
A girl was ten on her last birthday, and will be twelve on her next birthday. How is this possible?
What is up that’s also down? What’s a smile and a frown?
What has a big mouth, yet never speaks?
Has no feet, but travels far. Is literate, but not a scholar. Has no mouth, yet clearly speaks.
Do what he says and you'll be fine, don't and you lose the game.