Good Riddles

Question: You see us everyday, but you never see us together. We appear everywhere but never are we together at the same place. Who are we?

Question: A pond with dimension of 6m by 3m wil be filled of water lilies at exactly 30 days. Each day the number of water lilies will be doubled. First day 1, second day 2 etc... On what day it will fill half of the pond?

Question: I'm 10 years old my brothers half my age now I'm 100 years old how old is my brother now?

Question: What grows when it eats, but dies when it drinks?

Question: Would you rather enter a pool with a man eating shark, or a pool with ten electric eels?