Good Riddles

Question: I am alive yet not alive. I can fly yet always on the ground. I am delicate yet can lift tonnes. What am I?

Question: What word is shorter when you add two letters to it?

Question: I can be cracked, I can be made. I can be told, I can be played.

What am I?

Question: Four cars come to a four way stop, all coming from a different direction. They can't decide who got there first, so they all go forward at the same time. They do not crash into each other, but all four cars go. How is this possible?

Question: How many people do you need to have the odds be in favor (at least 50% chance) of two people having the same birthday?