life or death

[theprinceofsorts]

A prisoner is facing two doors. One - but which one? leads to freedom, the other one to death.
Each door has a warden, and the prisoner knows one of the two wardens always lies, whereas the other one always says the truth. Of course, he does not know who is the liar.
He is allowed to ask one and only one question to whichever of the guards he chooses before picking up the door he will go through. Which question will save his life, enabling him to pick up the right door?

[Bigpineguy Retired]

The only thing that I could think of is " Warden, I am the prisoner standing here?"


BPG~

Edit: Shoot, though that question makes sense, I don't think that would save his life....let me think about it some more...

[tronics]

Hahaha I swear this is a scene from that old movie Labyrinth.

So for the answer lets name the doors door1 and door2 respectively. Likewise the Warden of door1 is Warden1 and the Warden of door2 is Warden2.

The prisoner should ask Warden1 if Warden2 would tell him that Door1 leads to freedom.

If Warden1 says YES then that means that Door2 is the door to freedom because:
if Warden1 is the liar then Warden2 always tells the truth in which case Warden2 WOULDN'T say door1 was the door to freedom and therefore would say door2 is the door to freedom.

if Warden1 is the truthful one then Warden2 would be the liar and that would mean that him saying door1 is the door to freedom is a lie so that means door2 is the path to freedom

Either way door2 is the path to freedom

If Warden1 says NO then that means Door1 is the path to freedom because:

if Warden1 is the truthful on then Warden2 always lies so if he said door1 was not the path to freedom and is lying then it is the path to freedom
if Warden1 is the liar then Warden2 would say door1 is the path to freedom and would be telling the truth.

so either way door1 is the path to freedom.


So to recap the prisoner should ask one of the Wardens (warden1) if the other one (warden2) would say door1 is the path to freedom. If the answer is YES then you know door2 is the path to freedom. If the answer is NO then you know door1 is the path to freedom.


What a long answer!

[theprinceofsorts]

good! it is pure maths, actually. A liar and a truthful person taken together always end up with a lie...