Riddle #295

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Question: John has three daughters who are all unmarried. The youngest always lies, the oldest always tells the truth, and the one in the middle either tells the truth or lies. A very rich young man comes to John's house and says he wishes to marry one of his daughters. Naturally he wants to marry the oldest or the youngest so he will always know if she is lying or telling the truth. John agrees but says he can only ask one of the girls a yes or no question to decide which one he marries. They all look the same age.

What one question does he ask one of the daughters at random to figure out which daughter is the youngest or oldest?

Answer: "Is she older than her?" (He would ask one of the daughters if one of the other daughters is older than the last daughter). He always should pick the younger daughter based on what he knows. If he asks the older daughter and she says yes, then the youngest daughter will be known. If he asks the older daughter and she says no, then the youngest daughter is the other one. If he asks the youngest daughter and she says yes, she is lying and he will still pick the oldest. If he asks the youngest and she says no, he will just pick the other like in the first case. If he asks the middle daughter it doesn't matter because both will be acceptable choices.

Riddle Discussion

By: shabihusain786 on 31/7/16

Is john your father?
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By: shabihusain786 on 31/7/16

Is john your father?
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By: Kaio on 25/4/15

My answer was "If I asked them, would both your other sisters say you have never lied?" If the man asked the oldest or the youngest sister, they wouldn't be able to answer since they can't, without a doubt, tell the truth or lie given the question. Since the middle sister could answer either way, they don't know the answer. If I ask the middle sister this question, however, she would know, without a doubt, that the oldest would say "Yes" and the youngest would say "No," so she could answer with the truth or a lie. Just the fact that she could answer means that she's the middle.
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By: Rawad555 on 24/7/14

The answer of the riddle is not correct because if the three look the same age he wont know if he chosen the oldest or the youngest to ask her the question.So he wont know if she is saying the truth or lying.If he ask the oldest and said yes he wont know that she is saying the truth so he could think that she is the youngest and she is lying he will pick the wrong girl.
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By: Bro on 1/12/13

Ask this question..."you, is she older than her"? The goal is to never choose the middle daughter. When the answer is yes, always pick her...when the answer is no, always pick she. This way you will always pick the youngest or the oldest, but technically you still wont know if she's lying or not:)
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