Can you guess this riddle?

So there are two doors and one door leads to freedom, one leads to death. You don't know which door is which.

Two guardians guard the doors. One always tell lies and the other always tells the truth. What question can you ask to find out which door is which? You can't open the door till you absolutely know which is which

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TheOneyouwerewarnedabout · 46-50, MVIP

To solve the puzzle, you must ask one guard (it doesn’t matter which one) which door the other guard would say leads out. Both guards will indicate the same door, which will be the door that doesn’t lead out. For purposes of this explainer, we’ll call the doors A (the safe door), and B (the knock, knock, knocking on heaven’s door). Let’s discuss:

Scenario one: The guard you ask is the one who lies.

If the guard you asked is the one who lies, then he will lead you astray by telling you (falsely) that the other guard – the truthful guard – will point you towards door B. This makes door A the safe bet.
Scenario two: The guard you asked is the one who tells the truth.

If the guard you ask is the one who tells the truth, he will tell you (honestly) that the other guard – the lying guard – will point you towards door B. This makes door A the safe bet.

Tanner07 · M

@theoneyouwerewarnedabout: yes!

Dewms

"Are you a liar?" then ask them to bend over

Tanner07 · M

@Dewms: ...

RealtaReoite · 61-69, M

Ask either guard: "If I were to ask you if your door leads to freedom, would you say 'yes'?

If he says "yes", go that way. If he says "no", go the other way.

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RealtaReoite · 61-69, M

Suppose he's a truth teller and it's the door to freedom, he'll say "yes", right? All good. Go that way.

Or if he's a truth teller, and it's the door to death, he'll say "no". So go the other way.

Now, suppose he's a liar and it's the door to freedom. If I asked him if it's the door to freedom, he'd lie and say "no". But I didn't ask him that. I asked him "IF I ASKED YOU if that's the door to freedom would you say "yes"? but we just established that his answer to the direct question would be "no". But since he's a liar, he'd say "yes" to the actual question I asked. And that would be the way to do.

The last case is left as an exercise to the reader.