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Friday puzzle -- three hats

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Friday puzzle -- three hats

#1

Friday puzzle -- three hats

Alex Y

by Kevin J. Lin

The three wisest sages in the land were brought before the king to see which of them were worthy to become the king's advisor. After passing many tests of cunning and invention, they were pitted against each other in a final battle of the wits.

Led blind-folded into a small room, the sages were seated around a small wooden table as the king described the test for them.

"Upon each of your heads I have placed a hat. Now you are either wearing a blue hat or a white hat. All I will tell you is this- at least one of you is wearing a blue hat. There may be only one blue hat and two white hats, there may be two blue hats and one white hat, or there may be three blue hats. But you may be certain that there are not three white hats."

"I will shortly remove your blind folds, and the test will begin. The first to correctly announce the color of his hat shall be my advisor. Be warned however, he who guesses wrongly shall be beheaded. If not one of you answers within the hour, you will be sent home and I will seek elsewhere for wisdom."

With that, the king uncovered the sages' eyes and sat in the corner and waited. One sage looked around and saw that his competitors each were wearing blue hats. From the look in their eyes he could see their thoughts were the same as his, "What is the color of my hat?"

For what seemed like hours no one spoke. Finally he stood up and said, "The color of the hat I am wearing is..."

Re: Friday puzzle -- three hats

#2

Tough one!

Bill Earl

Assuming that the sage had complete confidence in the sagacity of his colleagues, the fact that the answer wasn't obvious makes the answer obvious. ;)

Re: Friday puzzle -- three hats

#3

Re: Tough one!

Alex Y

It sounds like you have the right answer, with the reasoning very concisely stated!

Re: Friday puzzle -- three hats

#4

Explanation

Alex Y

Kudos to Bill for getting this one.

Interestingly, you don't even have to know what color hats the winner saw to know that he answered that he was wearing a blue hat. And knowing all the possibilities is key to why a person seeing two other blue hats reasoned that we was also wearing a blue hat.

If there were two white hats and one blue hat, the wearer of the blue hat would see the two white ones and, having been told that there was at least one blue hat, would have claimed to be wearing a blue hat.

If there were two blue hats and one white, then each of the wearers of blue hats would see one of each and reason as follows: "If I were wearing a white hat, the wearer of the blue hat would see two white hats, so would have known he was wearing a blue hat, and claimed the job. Since he didn't, I must be wearing a blue hat."

In the case mentioned, the contestant saw two blue hats. He realized that if he was wearing a white hat, both of the other two would have seen one blue and one white hat, and claimed to be wearing a blue hat, reasoning as in the above paragraph. He was confident that they had had enough time to have figured that out if he were wearing a white hat, and since no-one has made such a claim, he must be wearing a blue hat.

The above is the solution I have seen. I suggest another solution based on meta logic: When the rules are laid out, I know the king to want to use this contest to find the wisest person. If anyone gets a white hat, the "playing field" of this contest is biased, so would not achieve the king's objectives. therefore, before the blindfolds are removed, I claim to be wearing a blue hat.

Anyone see a flaw in the solution in the paragraph above? I don't want to depend on such logic and find it wrong leading to my beheading if I ever am faced with such a situation!

Re: Friday puzzle -- three hats

#5

Re: Explanation

Bill Earl

Assuming of course that you have confidence in the King's wisdom as well!

Re: Friday puzzle -- three hats

#6

Dale Lenz

I would of kept my month shut!


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