[Guest]

You are locked in a cave, There are 2 doors. Behind 1 door is the way out and behind the other door, lies death. There are 2 guards standing in front of the doors. (Both guards are guarding both doors not one each). You are allowed to ask 1 question to each of the guards but 1 of the guards is a liar and will give the opposite answer to the truth and the other guard will only tell you the truth. What questions would you ask to determine which door is going to be the exit door?

Edited May 5, 2008 by ebony t

[Guest]

You are locked in a cave, There are 2 doors. Behind 1 door is the way out and behind the other door, lies death. There are 2 guards standing in front of the doors. (Both guards are guarding both doors not one each). You are allowed to ask 1 question to each of the guards but 1 of the guards is a liar and will give the opposite answer to the truth and the other guard will only tell you the truth. What questions would you ask to determine which door is going to be the exit door?

I would ask if you have checked/searched because this looks like a repeat topic, Why would they let you through - not good guards if they do?

[Guest]

You say to each one:

"Which door will the other guard tell me is the safe door?"

The truth teller will point to the death door, knowing that the liar will lie. The liar will point to the death door as well, telling the opposite of what he knows the truth teller would say. You now know which door is the death door, so you walk out of the otherone.

Or course, I always think with these thing that its so much easier than this. My non complicated solution? I say to one guard: "Am I a girl?" If he says yes (which I am), he is the truthteller. Then I ask the other guard which door is safe and go to the opposite exit, as he is the liar and would point me toward death.

It follows that if the first guard says "No, you are not a girl," then he is the liar. I then ask the other guard, who I now know to be the truth teller, which door is safe and follow his advice.

[Brandonb]

Locked in a cave? Nah, this thread is what's going to be locked. LIS was right, It's already posted HERE (and a few other places).

Ebony, click the text link in little red bar that says "Important: READ BEFORE POSTING."

This one could be searched for using key words "guard+truth+death"

Basically, a good rule of thumb is that if you didn't come up with it yourself, it's probably already been posted. So run a search.

[rookie1ja]

Welcome to the Den, ebony. This is one of my favorites. It is also the most repeated puzzle on this forum - still coming in new variations (stories) ... long discussion can be found in the thread entitled Honestants and Swindlecants III.

Check out the rules for this forum (link at the top) = Important: READ BEFORE POSTING - especially the part on doing a search before you post a puzzle.

Looking forward to new puzzles ... this topic is locked.