Wall Puzzle

[Kai Laddiman]

I've got a puzzle:

4 men were standing either side of a wall and they were facing it. They were each wearing a coloured hat, like so:

White (Wall) Black White Black

If any of them turned around or looked round the wall, they would get shot. To survive, 1 of them has to call out what colour hat they are wearing. What do they do?

[Gavin Chipper]

They know there's two of each? I think this has come up before. So I won't say anything.

[Jon Corby]

I think you may need more constraints on this puzzle...

[Ben Hunter]

To survive, 1 of them has to call out what colour hat they are wearing. What do they do?

He calls out what colour hat they are wearing.

[Joseph Bolas]

They know there's two of each? I think this has come up before. So I won't say anything.

I like this puzzle, but like you have said, I think it has come up before too. Sorry Kai.

[Dinos Sfyris]

I think you may need more constraints on this puzzle...

Yes. I have seen this puzzle before so will elaborate on the constraints, for those who have not seen it before.

4 men in coloured hats face a wall in the fashion Kai described: White (WALL) Black White Black
They are told there are 2 hats of each colour.
They do not know the colour of their own hat, only that of the men in front of them (that aren't obscured by the wall)
They are not allowed to cheat, take off their hat, look around, confer or give signals to other people, no reflections or guessing etc.
The men are told if they can figure out the colour of their own hat they must shout it out straight away, and they will be released.
The men are entirely logical. This is a logic puzzle after all.

Which man is the first to realise his hat colour? How does he realise this?
How many of the men in total figure out their hat colour and can be released?

Also in the version I heard there is a big scary puzzle-loving monster rather than someone threatening to shoot them which is better imagery IMHO!

Good effort from Kai though. More puzzles please The more original the better.

[kirsty]

White (WALL) Black White Black - two hats of each colour

so let's call them: ann (wall) carol susie des

• if des could see two white hats or two black hats then he could be sure he was wearing the other colour. since he can see carol in black & susie in white he can't rule out either colour for himself.
• susie doesn't hear des call out so she knows that she and carol must have different colour hats, since she can see carol has a black hat she calls out 'white'
• so long as carol knows where susie was standing she'll recognise susie's voice calling out 'white' and work out that she must have a black hat.
• des and ann get fed to the puzzle loving monster (you can shoot ann.)

[Kirk Bevins]

des and ann get fed to the puzzle loving monster (you can shoot ann.)

Ouch. That must suck.

[Michael Wallace]

des and ann get fed to the puzzle loving monster (you can shoot ann.)

Ouch. That must suck.

For the monster, right?

[Dinos Sfyris]

des and ann get fed to the puzzle loving monster (you can shoot ann.)

Ouch. That must suck.

For the monster, right?

lmao! Absolutely correct.