Five hats

 

 

Question:

There are 5 hats. Three are blue, two are red. They are placed in a box and mixed up. Three people are blind folded and standing in a line one behind the other facing forward. Each person reaches into the box, one at a time and withdraws a hat which is then placed on their head. Their blind folds are then removed. The first person in line knows the color of her hat and of the two people behind her. How does she know this? ( she cannot turn around and look behind her and they cannot speak)

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Solution: The text of the riddle is corrupted. First, the last of the persons in line (who sees the other two) says: I don’t know what is the color of my hat. Then the second says: I don’t know what is the color of my hat.

The first in line reasons as follows: If both me and the one in the middle had red hats on, then the third person would know that he has to wear blue since there are only two red hats. So I and the second guy don’t wear two red hats. So we either wear two blue, or a red and the blue.

Now the second guy can figure as much as I did, so if I was wearing a red hat he would know that he has to wear blue. He doesn’t know what is the color of his hat, so I can’t wear red, so I must wear blue!

 

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