Riddle courtesy of William Wu’s riddle archive.
There are 3 black hats and 2 white hats in a box. Three men (we will call them A, B, & C) each reach into the box and place one of the hats on his own head. They cannot see what color hat they have chosen.
The men are situated in a way that A can see the hats on B & C’s heads, B can only see the hat on C’s head and C cannot see any hats.
When A is asked if he knows the color of the hat he is wearing, he says no.
When B is asked if he knows the color of the hat he is wearing he says no.
When C is asked if he knows the color of the hat he is wearing he says yes and he is correct.
What color hat and how could he know?
Hint: Write down all permutations of hats and test them against the way each man answered.