Good Riddles

Question: What has ten letters and starts with gas?

Question: What flies when it's born, lies when it's alive, and runs when it's dead?

Question: You have three coins. One always comes up heads, one always comes up tails, and one is just a regular coin (has equal change of heads or tails). If you pick one of the coins randomly and flip it twice and get heads twice, what is the chance of flipping heads again?

Question: In spring I look gay, Covered in a green array, The warmer it gets the more clothing I wear, As the cold grows, I throw away my clothes.

What am I?

Question: You are running in a 400 meter race and you overtake the last person, what place are you now in?