Good Riddles

Question: What is heavy one way and not the other?

Question: A wooden block is floated on water. What can be placed on it to reduce its weight?

Question: There are 5 frogs, 1 die. How many left?

Question: What room can no one enter?

Question: 28th Feb, 2015 Josh went to rob a bank. He threatened to kill the cashier if he didn't open the vault. The cashier told him the vault is not opened with keys but with a password. You can't kill me since I'm the only one who knows the password and everyday the password is different. Josh shot the cashier, entered the password, opened the vault and stole all the money. What is the password?