Humanities Homework Help

one woman has 5 hats in the bag . 3 black and 2 white. he places 3 black hat on three men`s head who are supposed to guess what color each have on the head by looking at each other. they also know there is another 2 colors left in the bag not knowing what are those either. one brave man says that he is sure he is wearing black hat . how can he prove it?

please explain in details