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Home > News > News Archive > Puzzle corner – Black and white hats

Puzzle corner – Black and white hats

Black and white hats-3

Welcome to this month's puzzle corner. If you can work it out there are prizes for the first ten correct answers we receive!

Four prisoners are given the opportunity of release and freedom if just one of them can work out the answer to a simple puzzle. However, if they take part and one of them gives a wrong answer, or none of them can work it out at all, then their sentences will be doubled.

The prisoners accept the challenge and are told that there are four hats. Two white and two black. Each prisoner will have a hat placed on his head while blindfolded. When each man is wearing a hat the blindfolds will be removed. The prisoners will not be able to see their own hats and the challenge is for one of them, just one, to work out the colour of the hat he is wearing, black or white? This of course can be done by observing the hats the other three prisoners are wearing. Simple really.

But there's a twist. To make it more interesting three prisoners have to stand in a line facing a brick wall. The prisoner at the back, let's call him A, stands on a box and can see both of the prisoners in front of him, B and C. Prisoner B stands on a smaller box and can only see prisoner C, who in turn can only see the wall. The fourth prisoner, D, stands on the other side of the wall and can see nothing of the other prisoners, nor his own hat. They are not allowed to turn around, or converse in any way.

The prisoners are told that they have 10 minutes for just one of them to work out what colour hat he is wearing and then call out the answer. But remember, they are only allowed one answer, and if just one of them gets the answer wrong they will all have their sentences doubled. Prisoners B and C are not wearing the same colour hats.

Within the time allowed one prisoner calls out the right answer. Can you work out which one and how he knew?

E-mail your answers to andrew@controlinmotion.com There's a prize of a 2 Gig Motor Technology memory stick for the first ten correct answers we receive. Remember to include your address if you want the prize.