15) 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?

Now the problem that i am facing with this question is that in the answer key the solution to this question is given as:” if i were to ask you whether the right branch leads to the ruins would you answer yes”. But how would the response to this question help me determine which branch to take because if he is a liar he would respond negatively even if the right branch actually leads to the ruins , as he is a liar he has a tendency to give a wrong response even to that question.