Black and White Hat Logic Puzzle

[blut wump]

Four guys go into a room and are blindfolded. They each blindly pick a hat from a bag of six hats, known to contain 3 Black hats and 3 White hats. They each don the hat they picked.

The first guy removes his blindfold so he can see what colour everyone else's hat is and he's asked whether he knows the colour of his own hat. He says 'no' and leaves the room.

The second guy removes his blindfold and is asked whether he knows the colour of his own hat. He says 'no' and leaves.

The third guy removes his blindfold and see a White hat on the head of the fourth guy. He now knows the colour of his own hat.

What colour hat is he wearing and how does he deduce it? At no time can any guy see the hat on his own head.

 

[silverfish]

Black, guys 1 and 2 also had black. He correctly guessed that #1 saw 2 black and 1 white when he looked. Also that #2 saw 1 black and 1 white hat when he looked. Am I close or what?

 

[blut wump]

Pretty much spot on.

Since there are three White and three Black hats to start with in the bag:

When guy1 looks, everyone knows that he didn't see three hats the same else he'd have known that he had one of the other colour.

When guy2 looks, he's hoping that he sees two hats the same because then he'll know that he has the other colour. Since he can't say what colour he has the remaining two know that they don't have the same colour hat.

Guy3 then sees a White hat and so his is the the other colour: Black.

I don't think we can know what colour hats guys 1 and 2 were wearing, only that the last two must have different colours.