You Walk Up To A Mountain That Has Two Paths
Riddle: You walk up to a mountain that has two paths. One leads to the other side of the mountain, and the other will get you lost forever. Two twins know the path that leads to the other side. You can ask them only one question. Except! One lies and one tells the truth, and you don't know which is which. So, What do you ask?
Answer: You ask one twin, "Are you twins?". If he says "Yes", he is telling the truth. Therefore, you ask the other twin which way to go and go the opposite way because he is lying. If he says "No", he is the liar and you ask the other twin which way to go because he is telling the truth.
Source: https://www.riddles.com/984
