Thursday, February 17, 2011

Color of My Hat

Cannibals ambush a safari in the jungle and capture three men. The cannibals give the men a single chance to escape uneaten.

The captives are lined up in order of height, and are tied to stakes. The man in the rear can see the backs of his two friends, the man in the middle can see the back the man in front, and the man in front cannot see anyone. The cannibals show the men five hats. Three of the hats are black and two of the hats are white.

Blindfolds are then placed over each man's eyes and a hat is placed on each man's head. The two hats left over are hidden. The blindfolds are then removed and it is said to the men that if one of them can guess what color hat he is wearing they can all leave unharmed.

The man in the rear who can see both of his friends' hats but not his own says, "I don't know". The middle man who can see the hat of the man in front, but not his own says, "I don't know". The front man who cannot see ANYBODY'S hat says "I know!"

How did he know the color of his hat and what color was it?

1 comment:

  1. Well this is how I derived to Answer

    1)Let us see

    Case 1:All the hats can be Black
    Case 2: 2 of the hats are white
    Case 3: 2 of the hats are Black

    In total there are 3 black hats and 2 White hats

    Now lets start form Last person who said "I don't know"

    He could see the hats of both the persons in front.Had they been White.He knew he was wearing a Black hat and he would have told them but he said I don't know.

    Which means that two Hats ore White is not feasible and is removed

    So we have 2 cases in all now

    Case 1: 2 Hats are black
    case 2: There is 1 black and 1 White Hat

    Above are the cases for 2nd Man in queue

    Now he can see the hat of the person in front if it was white he knew that he was wearing a Black Hat.But he was wearing a black hat so either his hat is white or black so he says I don't know.

    So for the third person only 1 case is left which says

    Case 1: 2 Hats are black

    Which means his hat was black and he said yes I know and hence he said that his hat was black.

    And all were saved....

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