Good Riddles

Question: Which is correct, 9 and 5 is 13 or 9 plus 5 is 13?

Question: I have roots that nobody sees,
I'm taller than any trees,
up and up I go,
but I never grow?

What am I?

Question: I fly, yet I have no wings. I cry, yet I have no eyes. Darkness follows me; lower light I never see.

What am I?

Question: There are 57 ducks walking to a pond. On the way, 15 get lost, 26 head back, and 16 make it to the pond.

What happened to the rest?

Question: You are playing a game of dodge ball with two other people, John and Tom. You're standing in a triangle and you all take turns throwing at one of the others of your choosing until there is only one person remaining. You have a 30 percent chance of hitting someone you aim at, John has a 50 percent chance, and Tom a 100 percent change (he never misses). If you hit somebody they are out and no longer get a turn.

If the order of throwing is you, John, then Tom; what should you do to have the best chance of winning?