Villager Logic Puzzle Each inhabitant of a remote village always tells the truth
or always lies. A villager will give only a “Yes” or a “No”
response to a question a tourist asks. Suppose you are a
tourist visiting this area and come to a fork in the road.
One branch leads to the ruins you want to visit; the other
branch leads deep into the jungle. A villager is standing
at the fork in the road. What one question can you ask the
villager to determine which branch to take?
I understand the textbook answer; which is:
“If I were to ask you whether the right branch
leads to the ruins, would you answer yes?”
But my question is if this answer is equally valid:
"Do either of these roads from this fork in the road lead to the ruins?"
Now the reasoning I have is that we know that one of the roads in the fork leads to the ruins. The villager, if he is a liar, will say no. (lie). If he is honest, he will say yes.
Is this sound?
 A: That will tell you whether he’s a liar or not, but you’ll need a second question to determine which fork to take. The textbook answer tells you the right fork, but you’d need a second question to determine whether your informant is a liar. There’s no way to get both pieces of information from a single yes/no question.
A: Oh it is a very nice, old, and mind blowing puzzle :)
The key to solve this puzzle, that is actually missed in this formulation (it's always had been asked in this formulation), the key is that both of the villagers knows each other! thus each of them knows who is the lair and who is not.
After this, the tricky part is to formulate the question, and the right question to ask is:
If I will ask you neighbor, what is the road that leads to the ruins, what he will answer?
Thus if you where asked the lair, he will tell you for sure into the jungle way.
While if you where asked the honest one, he will tell you the way into jungle too! (because he knows that his neighbor is lair!)
So despite of the person you will ask, you will simply need to take the opposite to the answer you have been told!
Very tricky :D
P.S:
Can you please tell me where you read about this puzzle? because I have been asked to solve it a long time ago and never faced it again.
