Brain Teasers
Truth or Lies
You are traveling down a path and come to a fork in the road. A sign lays fallen at the path indicating that one path leads to a village where everyone tells the truth and the other to a village where everyone tells lies. The sign has been knocked down so you do not know which path leads to which village. Then someone from one of the villages (you don't know which one) comes down the path from which you came. You may ask him one question to determine which path goes to which village. What question do you ask?
Answer
You point to either path and say, "Are you from this village?" If the person answers 'yes' then you are pointing to the truthful village, if they answer 'no' then you are pointing to the lying village.1)If you point to the truthful village what will a truthful person say in answer to your question?
2)If you point to the truthful village what will a untruthful person say in answer to your question?
3)If you point to the untruthful village what will a truthful person say in answer to your question?
4)If you point to the untruthful village what will a untruthful person say in answer to your question?
The answers to these questions are: 1. "yes", 2. "yes", 3. "no", 4. "no".
Note that in the two cases where the answer is "yes" you are pointing to the truthful village and in the two cases where the answer is "no" you are pointing to the untruthful village. Thus you can tell from the reply to which village you are pointing. You do not have to know to whom you are speaking.
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