Riddle: You are walking along a road and come to a crossroads. There is an identical twin at each road, and they look exactly the same. However, one twin always lies and one always tells the truth. You must continue on your path, but you are only allowed to ask one question of the twins to continue on the right path. What do you ask?
Answer: What would the other say? They will point you towards the wrong path, and you would take the other one.
At the crossroads Riddle Meme with riddle and answer link.
