There’s a semi-classic riddle that goes something like this:
Two men are at a fork in the road. One always tells the truth, and the other always lies. You need to know which fork in the road to take to get to your destination. You can only ask one of the men one question before deciding which fork to take. How will you figure out which fork to take?
The answer goes something like this: you ask one of the men, “If I asked the other guy which way was the correct way, what would he tell me?” And then you take the other fork. This works because if the person you ask is the truth-teller, then he’ll truthfully tell you that the liar would tell you to take the wrong path, so you take the other one. If the person you ask is the liar, then he’ll lie and tell you that the truth-teller will tell you to take the wrong path, so you take the other one.
It seems like everyone and their mom has heard of this puzzle. From where, I don’t know. But I’m sure you’ve heard of it, too.
Here’s an interesting variation I heard a couple of years back:
Two men, Jack and John, stand at an intersection. You know that one of them always tells the truth, and the other always lies. But you don’t know which one is Jack and which one is John, nor do you know whether Jack is the liar or if John is the liar. Asking only one of the men only one question, how do you determine whether Jack or John is the liar? In the same situation, again using only one question, how do you determine which of them is Jack? And one final catch: your question in each case must be three words or less.
Answer in the next post! I have to create suspense somehow…