Every man in a village of 100 married couples has cheated on his wife. Every wife in the village instantly knows when a man other than her husband has cheated, but does not know when her own husband has. The village has a law that does not allow for adultery. Any wife who can prove that her husband is unfaithful must kill him that very day. The women of the village would never disobey this law. One day, the queen of the village visits and announces that at least one husband has been unfaithful. What happens?
I give. When are you going to tell us slow people the answer? I know that it is not the Queens husband though.(?)
Everything could happen. There is no standard anwser. I thought there should have a better answer at the time I posted this. But as Frank pointed out, the interviwer could use this question to deduce something about a person by how they answer the question. Let's do some kind of different brain workout. What they would deduce about a person from the following awnsers: 1. People will ask the Queen who he was, if she doesnt know then it was the King. 2. All husbands get killed becuase wivies will start pointing fingers to the other's hushands. 3. Nothing. Because the wives wouldn't break the code of silience to disclose any identity of cheaters. Otherwise the whole comunity will get destroyed. 4. They laughted and ignored. Silly Queen, they thought, there are 99 cheaters! Not a news at all. 5. The problem doesn't say that the men are aware of what the women know. The queen is essentially tipping off the men that the women are on to them, and giving them an opportunity to escape. 6. The queen is threatening the order of their system. The men will just kill the queen. On the otherhand, let's think what Google is trying to get from the question: 1. They're trying to weed out applicants who assume conditions that make simple problems harder. 2. This is something related to a communication network with a code of silence or taboo against telling any wife her husband has cheated.
I finally get the answer (logically!) Frank & Biita, actually, your guess that every woman in the village kills their husband is correct: Every woman kills their husbands at the 100th day after the Queen made the announcement. I got this answer inspired by a similar "10 Monks with Blue Spots" puzzle. Let me explain. But we must assume that every woman in the villege be a very smart logician! Assume there is only one couple in the villege. The wife immediately proves that her husband is cheating because he is the only husband. At the end of the 1st day, she must kill her husband. Assume there are two couples (A and B) in the village. Wife A knows that husband B is cheating. She is expecting wife B kills her husband by the end of the 1st day. But this does not happen. So on the second day, wife A learned that wife B is aware that husband A is cheating and wife B expected that wife A to kill husband A. Therefore, at the end of the 2nd day, both wives kill their husbands. Assume there are three couples in the village. Each wife, assuming her husband be innocent, thinks that the other two are in the situation described in the "two couple assumption", and will expect them to kill their husband on the second day. When they haven't killed their husband to the third day, the wife learns that her assumption (her husband is innocent) is wrong. Therefore, at the end of the 3rd day, all three wives kill their husbands. And so on - if there are N couples, all wives will kill their husbands at the Nth day. That isn't funny. I guess nobody can answer this question during the interview, unless the interviwee is a super talent or already learned how to solve this kind of puzzle before.
Wait, I guess there is a problem in my reasoning. Wife A knows that Husband B is cheating but wife A does not know whether wife B knows husband B is cheating.Therefore, the 10-Monk Puzzle does not apply to this one. I am sorry.
