Please help with riddle solution

[peacefuljeffrey 0]

There's that old riddle about asking someone who always lies to answer a question. I think it goes something like there are two doors in a room, and one leads to certain death and one is an escape. There are two people in the room, one always lies and one always tells the truth, and you don't know which does which. You have to ask them which door leads to safety. What do you ask them that will indicate who is the liar and who is the truth-teller, so you can get the safe answer?

Thanks in advance for the help. Someone told me the answer to this a while back and I promptly forgot it, simple though I remember it being. Ugh!
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-Jeffrey
"With tha thoughts of a militant mind... Hard line, hard line after hard line!"

[skydyvr 0]

I've heard it and can't remember the details either, but it's all over the net.

. . =(_8^(1)

[Cudlo 0]

I cant remember the original answer to that (its 4am gimme a break). But, wouldn't it make sense to ask a question like "Does 2 plus 2 equal 4?" to each of them and whichever says no (the liar will always lie) is the liar? Please forgive me if im retarded right now.

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"People demand freedom of speech to make up for the freedom of thought which they avoid." - Kierkegaard

[blackwidow 0]

I think this one also goes, "you can only ask them one question..." too.

Just pick one of them, and ask them what the other would say; then do the opposite of that outcome.

So let's say door A is death, and door B is life; and person 1 is liar and person 2 is truth teller. If you pick the person on the right (truth teller) and ask them what the other guy would say. He would know that the other guy is a liar and that he stands in front of door (death); so he would say that the other would say life. Therefore door A is death. Go through door B. If the layout is the same and you ask the person on the left (liar) what the other guy would say (about door B), he would know that the other guy was standing in front of life and that since the other guy was the truth teller he would say life, so he would say death. Therefore door B would be life.

It's pretty early, but I think this works in all scenarios assuming that they know about each other.

I think the original place I saw this riddle was in an eighties movie, labrinth. Old.

[kallend 2,106]

You ask what the other would say, and do the opposite.

There are also versions for three, a truth teller, a liar (Bush), and one who alternately lies and tells the truth (Kerry). And even more complex versions that involve "Bush Apologists", people who can't tell the difference.

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The only sure way to survive a canopy collision is not to have one.

[kallend 2,106]

Quote

I think the original place I saw this riddle was in an eighties movie, labrinth. Old.

It's hundreds of years old. Variants are found in the works of Lewis Carrol (Alice in Wonderland, Through the Looking Glass).

...

The only sure way to survive a canopy collision is not to have one.