## The Labyrinth Puzzle (original xkcd)

A forum for good logic/math puzzles.

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Rhombic
Posts: 58
Joined: Wed Jan 01, 2014 11:42 pm UTC

### The Labyrinth Puzzle (original xkcd)

Visit this early comic to see the actual problem: http://xkcd.com/246/
Maybe, we should come up with a more accurate definition of "hard question".

Who
Posts: 108
Joined: Wed Oct 02, 2013 2:53 am UTC

### Re: The Labyrinth Puzzle (original xkcd)

Just ban any question which refers to:
Itself
The guard
The other guard
Any hypothetical situation/question
Any future situation
Truthfulness in general

For example:
"What would the other guard tell me" is banned because that refers to the other guard and a hypothetical question (You're asking about the situation where you ask the other guard)
"What would you tell me if I were to ask you" is banned because it refers to a hypothetical situation (You're asking about the situation where you ask...)
"What did you tell the last person to ask" is banned because it refers to a previous answer/question
"This door xor you are lying/the liar" is banned because that refers to the answer/the guard, also truthfulness.
"What will you tell the next person to ask..." is banned because it refers to a future answer/question.
"I heard that they're serving free beer outside, how long before it's all gone?" is still ok but might not work.

Moose Anus
Posts: 420
Joined: Fri Oct 14, 2011 10:12 pm UTC

### Re: The Labyrinth Puzzle (original xkcd)

Who wrote:"I heard that they're serving free beer outside, how long before it's all gone?" is still ok but might not work.

Guard says, "Free Beer?! Uh... I'll go check!" Then you peek through the door while the guard is gone.

HonoreDB
Posts: 160
Joined: Tue Feb 06, 2007 4:32 pm UTC
Contact:

### Re: The Labyrinth Puzzle (original xkcd)

Spoiler:
What's 2+2?
Then ask which door leads to freedom. They're guards, you're stuck in a labyrinth, surely you all have time for more than one question.

Who
Posts: 108
Joined: Wed Oct 02, 2013 2:53 am UTC

### Re: The Labyrinth Puzzle (original xkcd)

Moose Anus wrote:
Who wrote:"I heard that they're serving free beer outside, how long before it's all gone?" is still ok but might not work.

Guard says, "Free Beer?! Uh... I'll go check!" Then you peek through the door while the guard is gone.

Or you just use whatever door he used.
HonoreDB wrote:
Spoiler:
What's 2+2?
Then ask which door leads to freedom. They're guards, you're stuck in a labyrinth, surely you all have time for more than one question.

I think you get stabbed for asking too many questions.

Who
Posts: 108
Joined: Wed Oct 02, 2013 2:53 am UTC

### Re: The Labyrinth Puzzle (original xkcd)

Depending on how you interpret the wording of the question, the following might work:
Spoiler:
(This assumes that they're both standing in front of a specific door)
Is the liar standing in front of the door which leads to death?
If they answer "yes", you take the other door, if they answer "no", you take that door.
If you ask the liar standing in front of death, he'll lie and say "no". If you ask the truth-teller standing in front of death, he'll tell the truth and say "no".
If you ask the liar standing in front of freedom, he'll lie and say "yes". If you ask the truth-teller standing in front of freedom, he'll tell the truth and say "yes".
Parts you might be stabbed for:
"The liar" refers to one of the guards. But only questions referring to either "the guard" or "the other guard" were banned, not questions referring to "the liar" or "the truth-teller". Plead your case with the stabby guy.
"Liar" might be referencing truthfulness in general. But I'd say that this one is fine based on semantics, it's referencing a person not a concept (The truthfulness meant no asking anything involving statements/questions being lies/true).

teelo
Posts: 781
Joined: Thu Apr 08, 2010 11:50 pm UTC

### Re: The Labyrinth Puzzle (original xkcd)

"Hey guards. Nice day, isn't it? Look, you all look like you're really busy, so I'm just going to use my teleporter now to get out of here. See ya!"

Mike Rosoft
Posts: 63
Joined: Mon Jun 15, 2009 9:56 pm UTC
Location: Prague, Czech Republic

### Re: The Labyrinth Puzzle (original xkcd)

Too bad that the riddle doesn't have a solution, because none of the doors lead out of the labyrinth.

Klear
Posts: 1965
Joined: Sun Jun 13, 2010 8:43 am UTC
Location: Prague

### Re: The Labyrinth Puzzle (original xkcd)

Mike Rosoft wrote:Too bad that the riddle doesn't have a solution, because none of the doors lead out of the labyrinth.

Instead of a way out of the labyrinth the door contained a bobcat.

I guess if you are lucky, you get the door with a goat.

CharlieP
Posts: 397
Joined: Mon Dec 17, 2012 10:22 am UTC
Location: Nottingham, UK

### Re: The Labyrinth Puzzle (original xkcd)

This is my signature. There are many like it, but this one is mine.

qwertyuiop[]\
Posts: 4
Joined: Wed Apr 01, 2015 2:36 am UTC

### Re: The Labyrinth Puzzle (original xkcd)

What's the objective? The comic just says what the guards do or say.

rmsgrey
Posts: 3616
Joined: Wed Nov 16, 2011 6:35 pm UTC

### Re: The Labyrinth Puzzle (original xkcd)

Obviously you pick one door, get them to open another door to reveal a goat, and then ride the goat to freedom!

Ermes Marana
Posts: 44
Joined: Sun Feb 08, 2009 12:20 pm UTC

### Re: The Labyrinth Puzzle (original xkcd)

So basically, you are all asking me to figure out a way to get out of this impossible situation. Tricky.

One of the guards then kills himself and everyone except me.

I use a spear to scale the wall to safety (only the doors don't lead to safety).