Good Riddles

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

Question: How high would you have to count before you use the letter 'A' in the spelling of a number?

Question: At the end of a long dark cave there is a monster made of lead. Be careful. One twitch of the finger and you will release it.

What is it?

Question: I am a big threat to humanity,
but you wouldn't get rid of me even if you could.

What am I?

Question: Does an ounce of gold or an ounce of feathers weight more?