Riddle:
Three men, one of which is blind are in a room with their faces to a wall.
There is a bin with two blue hats and three red hats. Each of the men knows this.
Mrs. Potter comes in and places one hat on each of the men's heads so he can see the other two hats, but not his own. (Except the blind man who cannot see at all).
Mrs. Potter then asks the first man "What, sir, is the color of your hat?"
He looks at the other two hats and replies "Mrs. Potter, I don't know the color of my hat."
Mrs. Potter asks the second man, "My friend, do you know the color of your hat?"
The second man answers, " I'm afraid Mrs. Potter, I cant tell you because I don't know.
Mrs. Potter asks the blind man, "Sir, I know you can't see, but do you know the color of your hat?"
The blind man replies "Yes, I know exactly the color of my hat." And he gives her the correct answer.
What color is his hat, and how did he know?
Depends on whose logic you want to use.