03-02-2008, 09:22 PM
Here's another way to look at it -- some might find this easier...
If the first man doesn't see at least one white hat, then he knows his own hat must be white. Since he didn't know his own hat was white, he saw at least one white hat.
If the second man sees a red hat on the third man, he knows his own hat has to be white, because he knows that the first man had to see at least one white hat. But he sees a white hat on the third man, so he doesn't know whether his own hat is red or white.
The third man doesn't have to see anything by this time to know that his own hat is white.
-Gary-
If the first man doesn't see at least one white hat, then he knows his own hat must be white. Since he didn't know his own hat was white, he saw at least one white hat.
If the second man sees a red hat on the third man, he knows his own hat has to be white, because he knows that the first man had to see at least one white hat. But he sees a white hat on the third man, so he doesn't know whether his own hat is red or white.
The third man doesn't have to see anything by this time to know that his own hat is white.
-Gary-
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