Lost in the woods, you finally happen upon a rickety old bridge across a deep ravine. The ravine is too steep to go down and climb back up. You need to know if the bridge is safe. As 'luck' would have it, you recognize that on the other side of the bridge is that dreadful town, "Knight-and-Liarville". Everyone who lives there is a knight (who always tells the truth) or a liar (who always lies). You are tired and you've been lost in Knight-and-Liarville before. You see three men on the other side of the bridge.
You shout out: "Are you a knight?"
The first man says something, but you can't hear what he said.
The second man shouts, "He said he was a knight."
The third man shouts, "No, he didn't. He said he was a liar."
Which man do you ask to find out whether or not the bridge is safe?
(In reply to
re: Only 1 is safe to ask... by yo)
The third man's statement "No, he didn't" doesn't imply the first person is a knight. It only implies the first person SAID he was a knight.
And Nikki is right. If the third person had only said "He said he was a liar" the we would not know anything about what the first person did in fact say.
But since the third person (a known liar by his second sentence) contradicted the second person, in fact the second person must be a knight. I overlooked this point, and now agree with the earlier posts, though with slightly different reasoning:
The third man is a liar because of his second sentence.
The second man is a knight, because the liar contradicts him.
NOW we can infer that the first person did say "I am a knight." But we have no idea if he was telling the truth or not.
re(2): Only 1 is safe to ask...
