A king wishes to test three wise advisors to see who is the sharpest. He places a colored hat on each of their heads, telling them that each hat is either blue or red, and that at least one hat is red. Each advisor can see the hats of the other two, but not their own. The king asks Advisor A, 'Do you know the color of your hat?' A replies, 'No.' The king then asks Advisor B, who also says, 'No.' Hearing this, Advisor C immediately states the exact color of his own hat without looking in a mirror. What color is Advisor C's hat, and how did he know?
Red
If both A and B had white/blue hats (assuming red/blue), wait. If at least one is red, and A doesn't know, it's not the case that B and C are both blue while A is red. Since B also doesn't know, C realizes his own hat must be red, because if C were blue, B would have seen a blue hat on C and known his own was red (since A didn't know).
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Hard. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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