What Question Reveals the Gold-Bearing Door?

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Discussion Overview

The discussion revolves around a logic puzzle involving two doors, one of which conceals gold, and two guards—one who always tells the truth and one who always lies. Participants explore what single question can be asked to determine which door leads to the gold. Variants of the puzzle are also introduced, including a more complex scenario with three doors and three guards.

Discussion Character

  • Exploratory, Debate/contested

Main Points Raised

  • One participant presents the classic version of the puzzle, asking what question would reveal the gold-bearing door.
  • Another participant introduces a variant with three doors and three guards, complicating the scenario by adding a guard who randomly lies or tells the truth and an unknown language barrier.
  • A later post reiterates the three-guard variant, emphasizing its difficulty and labeling it as "the hardest logic puzzle ever."

Areas of Agreement / Disagreement

Participants do not reach a consensus on the question to ask in the original puzzle or the variants. Multiple competing views and approaches remain unresolved.

Contextual Notes

The discussion does not specify the assumptions or definitions that might influence the interpretation of the puzzles, nor does it resolve the mathematical or logical steps involved in finding a solution.

ashishsinghal
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There are two doors - one has lots of gold. You want to get gold . There are two guards (one for each door). Both of them know behind which door gold is kept. One guard always says the truth while the other always lies. You do not know who says the truth or who lies.
But the guards know who lies and who speaks truth. You can ask only one question. What would that be?
 
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https://www.physicsforums.com/showthread.php?t=100534
 
That's a classic one :biggrin:

What would the other guard tell you if I asked him "After which door is the gold?"?
Then pick the opposite door...

Here's a nice variants:

There are three doors, and there are three guards: one always speaks the truth, one always lies, and one randomly lies and speaks the truth. Furthermore, the speak in an unknown language, so you won't know what is yes and what is no.
You can ask three questions before deciding which door leads to the gold. Which questions would you ask?
 
micromass said:
There are three doors, and there are three guards: one always speaks the truth, one always lies, and one randomly lies and speaks the truth. Furthermore, the speak in an unknown language, so you won't know what is yes and what is no.
You can ask three questions before deciding which door leads to the gold. Which questions would you ask?

This is nearly an impossible puzzle, it's the hardest logic puzzle ever!
 

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