# Good Riddles

##### Riddle #604 (hard)

Question: There is a brick of gold and a brick of iron in a boat (both 10 inch blocks), if they are both dropped into the water which will make the water level higher?

##### Riddle #605 (hard)

Question: Tom wants to send Sally an expensive ring through the mail because they live thousands of miles apart. The only problem is that everything sent through the mail is stolen unless there is a lock put on it. Both Tom and Sally have plenty of locks and keys but they don't have any of the same locks or keys.

How can Tom send Sally the ring without it getting stolen?

##### Riddle #616 (hard)

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?

##### Riddle #617 (hard)

Question: An ant gets onto one end of a tight rope that is 1 meter long. The ant is traveling at 1 centimeter per second, but the entire rope is being stretched an extra 1 meter (1,000 centimeters) a second (it can be stretched forever).

Will the ant ever reach the other end of the rope?

##### Riddle: 100 prisoners and hats (hard)

Question: There are 100 prisoners lining up to go to jail. Each prisoner is wearing a hat that is either black or white. The prisoners don't know their own hat color, just the hat color of those in front of them in line (the first prisoner in line can't see anyone's hat and the last prisoner can see everyone's hat except their own). Starting from the back, one of the guards asks each prisoner what color their hat is. If they are correct they get to go free but if they are wrong they go to jail.If the prisoners get to discuss a plan, how can at least 99 of them be saved?