Complex Riddle

sarutobi

sarutobi

sarutobi

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I dont even know if theres a right answer here (it was inspired by this comic http://www.partiallyclips.com/storage/paradox_lg.png)

Anyway, you see a three headed dragon, you already know that

One head always lies
One head always tells the truth
One head always alternates between the two

They guard 2 doors, one leads to death the other dosnt

If you could only ask one head one question what would/could it be?

is there even a right answer?

(Im thinking if you asked any head what any of the others would say you'd still get the right answer?)
 
Timdog said:
isnt that out of a movie? i have a vague memory of something similar

but i would keep asking questions that i know the answer to and see which ones agree
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read my post closer, only one question for one head

gillywibble said:
Something along the lines of 'what would the other head say'.
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i know that would work if it was only the truth and lying head, but would it work if we introduced the third alternating head?
 
I've heard it before but without the third one, can't see what that really adding anything useful to the riddle.

I'd simply ask "how are you today?" and take my chances, it's 50/50...
 
Am I being dumb, probably, but surely if you ask the one that always lies: "Will this door lead to death?" he will either say yes or no which is a lie and so you do the opposite. So if he says yes then he's lying which means the other door does lead to death meaning that you can walk through the first door and be safe in the knowledge that you made the right choice?

I think the only way this riddle could be harder is if their's thre doors to choose from.
 
jonislost said:
Am I being dumb, probably, but surely if you ask the one that always lies: "Will this door lead to death?" he will either say yes or no which is a lie and so you do the opposite. So if he says yes then he's lying which means the other door does lead to death meaning that you can walk through the first door and be safe in the knowledge that you made the right choice?

I think the only way this riddle could be harder is if their's thre doors to choose from.
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yea but you dont know which head is which :)

i reckon its called a paradox dragon for a reason :p
 
The original riddle is a recursive question using a sequence of asking to define which head is which.

The key is the phrase "if it {the previous head} was lying". It could be possible to rephase it building into the predicate (the logic of the question) "if I were to propose going though the left door, .... , ... if it was lying leading to my death?"

In short these always sound complicated but they're not logically.


if you were to suggest we could only ask one head and not observe the state dialogue between he heads for the rest of the logic (as per the comic strip) then this is impossible to answer as (a) you can't define the state and (b) you can't tie the "which door leads to impending doom" with that state and reach a known outcome.
 
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jonislost said:
Am I being dumb, probably, but surely if you ask the one that always lies: "Will this door lead to death?" he will either say yes or no which is a lie and so you do the opposite. So if he says yes then he's lying which means the other door does lead to death meaning that you can walk through the first door and be safe in the knowledge that you made the right choice?

I think the only way this riddle could be harder is if their's thre doors to choose from.
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I think the riddles a bit over complicated and not very well explained. An example that I've heard is "that there are two people guarding doors, one lies, one is truthful, with one of the doors leading to death, you do not know which one lies, asking only one question - what would you ask?"

I think it's the whole 'not knowing who lies' thing, if not then the riddle is totally negated.

edit: too long, too late.
 
well the most common version of it is

You come across two guards guarding one door each. One door is right one is wrong. You know that one guard tells the truth and one lies. You can ask one guard one question. What do you ask?

The answer is "What would the other one say is the right door?"

No matter which guard answers his answer will be the wrong door. This is because the truth teller will tell you the wrong door because the the lier would tell you the wrong door if you asked for the wrong one. And the lier would tell you the opposite of the truths answer, which would mean he would say the wrong door also. So go for the opposite of the answer your given.

But how would it be affected by a third alternating guard?
 
^^ that won't work because for example, in the case where the third head is the alternating head, the answer can be either false or true.

I'm not totally sure how to prove it, but I think this is impossible and requires at least two questions.
 
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