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The liar, the truth teller....and the random answerer


Best Answer Writersblock , 30 July 2007 - 01:31 AM

Martini,

Spoiler for ...
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#41 Martini

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Posted 15 June 2008 - 01:32 PM

Welcome to the boards, smarties. See the post immediately before yours. ;)
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#42 etisayus

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Posted 24 June 2008 - 01:03 PM

Keep asking the men if they are the liar and when one of them says yes he is the random man...lets lable them L T R

We have eliminated R it might take a few times but that is the only possible way to elminate him is to keep asking.

Now ask either the L or the T (the two left) but since we dont know which is which we will say 1 and 2

Ask 1 if 2 would say he is a liar if 1 says YES then he is the one telling the truth if he says NO then he is the liar.

THIS IS THE SOLUTION im sure there are probably more ways but this is the easiest ;)



There is no gurantee that random man will say yes as we have to ask only 3 questions.
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#43 AnwarSiddiqui

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Posted 17 July 2008 - 03:24 PM

There is a truth teller (always tells the truth), a liar (always lies), and one that sometimes answers truthfully and sometimes lies. Each man knows who is who. You may ask three yes or no question to determine who is who. Each time you ask a question, it must only be directed to one of the men (of your choice). You may ask the same question more than once, but of course it will count towards your total. What are your questions and to whom will you ask them?


After implementing all the set theory that I knew of, I had to get down to drawing a flow chart of possible combinations and a flowchart of all the possibilities. Well one thing is pretty well defined that there will be a yes or no answer to any question that I will as. But for every question the Truth teller will always answer the truth, the liar will always tell a lie and the random person may either tell the truth or a lie, there is no way of being confirm about that.

I tried my best and the problem does solves in three questions but in two particular cases I can only identify one of these three as a lier or a truth teller. This means that if I have atleast 1 more question then I can be sure about all three of them.

Will such a solution that I am 100% sure to find the identity of atleast one person be acceptable?
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#44 AliceJH

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Posted 01 August 2008 - 04:00 PM

Q1 - To first man "Do either of the other two ever tell lies?"

At least one of them must be a compulsive liar (given) so
If first man's answer = Yes, he is either T (always tells truth) or R(random - on this occasion telling truth)
If first man's answer = No, he means the other two always tell truth which is not possible , so he is either L (compulsive liar) or R (random - telling lie on this occasion)

I'm not sure how to proceed but is this along right lines?
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#45 EyesOfTheDead

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Posted 08 August 2008 - 05:21 AM

I have become particulary interested in this site, and I have heard this riddle long ago. The solution...

Spoiler for Solution

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#46 nogox5

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Posted 08 August 2008 - 03:57 PM

I really dont like the "no answer" solutions because then its not really a yes or no question anymore, it now has an extra answer, and if the truth teller and liar have the option of not answering then the random person might randomly decide not to give an answer either, and then it would be unsolvable.
Also a person wouldnt just stare blankly into a question they couldnt answer, they would say "i dont know", of course the liar couldnt admit that he didnt know and so he would have have to lie about knowing and would just have to guess, and even if it got it right, he would still be lying, he was just lying correctly, but still lying at the moment that he gave the answer. And under the same logic the random could lie and give the "i dont know response", again leading to an unsolvable solution.

Spoiler for A non-no-response solution

Edited by nogox5, 08 August 2008 - 04:02 PM.

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#47 EyesOfTheDead

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Posted 09 August 2008 - 12:30 AM

If he says "yes" you know hes the liar


How do you KNOW he's the liar? No matter what the answer to that question is you can never distinguish who is who.
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#48 Loaner

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Posted 15 August 2008 - 10:04 PM

Spoiler for This will Work

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#49 Loaner

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Posted 15 August 2008 - 10:08 PM

Spoiler for This will Work


Of course this implies random alternates between truth and Lies. This is how I heard this riddle before and assuming it is the intent.
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#50 Martini

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Posted 15 August 2008 - 10:50 PM

Of course this implies random alternates between truth and Lies.

"and one that sometimes answers truthfully and sometimes lies"
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