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A fun math problem:

Three wise witches are told to line up in a way so that the last only sees the two in front, the middle one only sees the one right in front of her, and the first witch sees no one. They are told that each of them will have a hat put on their head, either black or white. These are chosen (they are told) from three white and two black hats. There are no mirrors and no trickey. They are told that whoever says the color of their own hat correctly gets a prize. Whoever says it incorrectly will melt. Once they get the hats on their heads, there is a long silence in which the witches think. Finally, the first witch says that she is wearing a white hat, and gets a prize. How did she know?

Answer to last week's problem: we willc ome back to this another week!