Truth or Dare!

Math isn't just numbers and shapes. It's logic too. The riddle in the video clip below from the movie Labyrinth is modeled after puzzles by logician Raymond Smullyan (whose books I highly recommend!!). Would you have figured out the right door to go through? Below the clip is a riddle for you to figure out. Good luck!




You are on a new reality TV show, you are the last survivor. You have dropped by parachute on a very bizarre island in the middle of the Pacific. There are two types of people living on this island, Northerners, who ALWAYS tell the truth, and Southerners who ALWAYS lie. You will win one million dollars if you can figure out the identity (Northerner or Southerner) of each of three people that you are presented with. If you cannot figure it out, you don't get the money, the program doesn't air, and you're left on the island for life.

The first of the three natives says something, but you don't hear it. The second of the natives says, "The first guy said he was a Southerner." The third native says, "Don't believe the second guy; he's lying. What the first guy said was the truth."

Who's who?