Where truths meet lies
This party of locals is made up of two classes of people: warriors and lords. They are as much different as they are the same. The crucial thing you need to know about them is that warriors always tell the truth, and lords always lie. There are no exceptions to this rule.
Two people stand guard next to each other, watching the area. One wears green and the other red. A sign tells you that you can pass if you can correctly identify which type of citizen each of them is: Are they a warrior or a lord?
The one in green says: “There’s at least one lord standing before you.” Simple enough, but you can glean much information from that sentence. What type of islanders are they?
You answer correctly and continue your trek. Soon, you reach a fork in the road and another pair of locals standing guard, waiting for you to arrive.
This time, you know for sure that one of them is a lord and one is a warrior. And, as luck would have it, they know where your hotel is. However, you don’t know which is which. To find out which direction leads you back to your residence, you are allotted just one question for them to answer. What question do you ask? (Hint: Decide on a query that both a warrior and a lord would have to provide the same answer to.)
question one: Green is a warrior, red is a lord. This remains true if the one in green is a warrior or a lord. But, if green were a lord, they’d be lying. So, green can only be a warrior, making red a lord. question two: Which direction would the other person tell me to go to get me in the right place? If the person you ask is a warrior, the other must be a lord. The lord would lie and say the opposite of where to go. If the person were a lord, the other would be a warrior bearing the truth—but the lord would lie about what the warrior says. In either case, you would get the opposite of the correct direction.