Person A, B, C, and D are all sitting in a room blindfolded. A hat is placed on each person's head and they are told it is either red or blue. In fact, each person was actually given a red hat. Once the blindfolds are removed each person can see what color the other people's hats are, but they cant see their own hat.
It is announced that there is at least 1 person wearing a red hat. First A, then B, then C, then D are asked what color hat he is wearing. Everyone can hear the other answers. What does each person respond (A is asked the question first-he responds-then B is asked the question after he hears A's response etc)