Fun Riddles

Question: Travel a mile and I will change.
Travel a million and I will end as I started.

What am I?

Question: You have 7 tennis balls that are all identical but one of them is slightly lighter than the others.

Using a balance scale and only two separate weightings, how can you find the light tennis ball?

Question: When you need me, you throw me away. But when you're done with me, you bring me back.

What am I?

Question: You are surrounded by a 100 foot wide and 100 foot deep moat. You have a 40 foot tall ladder, matches, a gallon of water, and as much rope as you need.

How can you get across the moat?

Question: A man was found dead in his study. He was slumped over his desk and a gun was in his hand. There was a cassette recorder on his desk. When the police entered the room and pressed the play button on the tape recorder they heard: "I can't go on. I have nothing to live for." Then there was the sound of a gunshot. How did the detective immediately know that the man had been murdered and it wasn't a suicide?