There are 3 prisoners inside a cage. All the prisoners are blind folded and wearing hats. They are told there are 5 hats all together, 2 blue hats and 3 red hats. If one of them can answer what color hat they are wearing they are all set free. However, they have no idea what color hat they are wearing, only what color hat the other prisoners are wearing. They are also not allowed to tell what color the others are wearing. So the game begins: The first prisoner takes off his blind fold. The guard says "What color hat are you wearing?" and the first prisoner says "I don't know." The second prisoner takes off his blind fold. The guard says "What color hat are you wearing?" and the second prisoner says the same thing, "I don't know" Now the third prisoner didn't even need to take off his blind fold. He already knew the answer. He said, "Sir, I know I am wearing a red hat" The guard smiled and all the prisoners are set free. Why? If the first prisoner saw the other prisoners blue hats then he knows he's wearing a red hat because there are only 2 blue hats and 3 red hats. But he sees one guy wearing blue and one guy wearing red, so he says "I don't know." The second prisoner took off his blind fold and the same thoughts occur. If he saw the other prisoners wearing all 2 blue hats, then he knows he's wearing red. Instead, he sees one guy wearing a blue hat and the other guy wearing a red hat. So he says "I don't know" Now the third prisoner doesn't even need to take off his blind fold. Why? He heard the other prisoners saying they don't know, which led him to believe that all they saw was blue and red hats. That means if he takes of his blind fold he will see that both of the previous prisoners will be wearing blue hats and since there are only 2 blue hats available, he must be wearing a red hat.