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        riddles >> easy >> A Liar And A Thief
        
(Message started by: truemuffinman on Aug 22nd, 2006, 2:10pm)
Title: A Liar And A Thief
Post by truemuffinman on Aug 22nd, 2006, 2:10pm
You come to a fork in the road. You decide to take the road to the left, when you see a theif hiding behind a tree at the end. You immediatly turn back to go down the right road. You see a liar at the middle of the road, when he calls out to you. "There are three murderers down this road... I'd go the other way if I were you and lose your money rather then your life."

Things you know about the liar and the thieves:

  • The liar has a very loose relationship with the murderers, meaning that they wouldn't kill him, and he wouldn't lie to them, but that's where it ends.
  • The liar only lies 90% of the time; 10% of the time he tells the truth.
  • The liar would not do you any harm if you pass him.


Things about yourself:
  • You are semi-strong, meaning that you could probably take out one murderer, but not 3.
  • Although you are pretty strong, thieves are extremely quick, meaning that he would steal from you before you had a chance to fight them.


Assume that:
  • You must take either one road or the other, there are no shortcuts or alternative passages.
  • You must do it righ there and then, you can't wait until they leave.
  • You are carrying about $500, and a thief would steal ALL of it.


What would you do?
Title: Re: A Liar And A Thief
Post by Three Hands on Aug 22nd, 2006, 3:26pm
Assuming that this is effectively forming the conundrum of "Down one route, you stand a 10% chance of death, but 90% of the time you are fine, meanwhile down the other route you are guaranteed to lose $500, which route do you take?", this is effectively asking whether you consider the utility of having an expected $450 or the utility of your life more worthwhile. Given I presume I have savings, or can alert police to the crime once I escape this situation alive, I would opt for the left road.

However, if I can get the "liar" to repeat his statement several times, through feigning deafness or some other ploy, I'd see what statement the liar adheres to most often is, and presume the opposite if there is suitable statistical likelihood.
Title: Re: A Liar And A Thief
Post by Icarus on Aug 22nd, 2006, 4:11pm
I go down the Thief road. There is a 10% chance that the thief road is better (based on the liar's second statement only). But even at 1% chance of death on the Liar road, the $500 just wouldn't be worth it. I value my life far more than that.

(And since I've already been down the Thief road to just shy of the end, I know that it is murderer-free.)

[e]Three-Hands hadn't replied when I opened this thread.[/e]
Title: Re: A Liar And A Thief
Post by towr on Aug 23rd, 2006, 12:45am
Some murderers might well have crept up on the path behind the thief.
The liar says you'll get away with your life if you take that path, and there's a 90% chance he's lying. There's a ten percent chance there aren't 3 murderers on his road, but then, there might be 4 or twenty, or two or zero.
Basicly, you don't have any usefull information to make a decision, because there's always unfavorable interpretations. The only thing you can be sure of is that you'll loose $500 if you choose the thief side.
Title: Re: A Liar And A Thief
Post by ezlonny on Aug 23rd, 2006, 2:35am
What is that fork doing in the road. It might also have been a spoon or a knife?
Title: Re: A Liar And A Thief
Post by Weazel on Aug 23rd, 2006, 10:12am
Considering there's a 90% chance of him lying that the left side is safer, I'd take the right side. If I do happen accross a murderer, I'd beat him up, take him back to the liar, and force the liar to tell me the truth.
Title: Re: A Liar And A Thief
Post by truemuffinman on Aug 23rd, 2006, 10:15am

on 08/23/06 at 10:12:28, Weazel wrote:
Considering there's a 90% chance of him lying that the left side is safer, I'd take the right side. If I do happen accross a murderer, I'd beat him up, take him back to the liar, and force the liar to tell me the truth.


You forgot something.

"'There are three murderers down this road..."

"You are semi-strong, meaning that you could probably take out one murderer, but not 3. "
Title: Re: A Liar And A Thief
Post by truemuffinman on Aug 23rd, 2006, 10:18am

on 08/22/06 at 15:26:34, Three Hands wrote:
Assuming that this is effectively forming the conundrum of "Down one route, you stand a 10% chance of death, but 90% of the time you are fine, meanwhile down the other route you are guaranteed to lose $500, which route do you take?", this is effectively asking whether you consider the utility of having an expected $450 or the utility of your life more worthwhile. Given I presume I have savings, or can alert police to the crime once I escape this situation alive, I would opt for the left road.

However, if I can get the "liar" to repeat his statement several times, through feigning deafness or some other ploy, I'd see what statement the liar adheres to most often is, and presume the opposite if there is suitable statistical likelihood.



Assume that the liar never changes his lie too. xD
Title: Re: A Liar And A Thief
Post by truemuffinman on Aug 23rd, 2006, 10:20am

on 08/23/06 at 00:45:33, towr wrote:
Some murderers might well have crept up on the path behind the thief.
The liar says you'll get away with your life if you take that path, and there's a 90% chance he's lying. There's a ten percent chance there aren't 3 murderers on his road, but then, there might be 4 or twenty, or two or zero.
Basicly, you don't have any usefull information to make a decision, because there's always unfavorable interpretations. The only thing you can be sure of is that you'll loose $500 if you choose the thief side.


Assume that the liar wasn't lying about that "safe road" part.
Title: Re: A Liar And A Thief
Post by Weazel on Aug 23rd, 2006, 11:08am

on 08/23/06 at 10:15:34, truemuffinman wrote:
You forgot something.

"'There are three murderers down this road..."

"You are semi-strong, meaning that you could probably take out one murderer, but not 3. "
Yes, but that's assuming

1. The liar was telling the truth about the number

and

2. The murderers are all together. In any case, since I have a keen enough eye to spot a thief, I would probably have a keen enough eye to spot three murderers and turn back before they get to me and go the other way.
Title: Re: A Liar And A Thief
Post by Sameer on Aug 23rd, 2006, 11:38am
I think this is an open puzzle with solution depending on person's choice.. the author may want to add more constraints or expand the puzzle to have one solution. I think!!  8)
Title: Re: A Liar And A Thief
Post by Grimbal on Aug 24th, 2006, 12:05am

Quote:
  • The liar has a very loose relationship with the murderers, meaning that they wouldn't kill him, and he wouldn't lie to them, but that's where it ends.
  • Although you are pretty strong, thieves are extremely quick, meaning that he would steal from you before you had a chance to fight them.

Go and kill the thief.  You'll get the money back after you had a chance to fight him.  Being a murderer, the liar will stop lying to you.


Quote:
  • The liar only lies 90% of the time; 10% of the time he tells the truth.

The liar speaks 2 statements, both of them to the effect that the right road is deadly.  Unless he told the truth twice, which happens 1% of the time, that road is safe.
Tell the liar you are taking the left road and take the right one.  It makes you a liar.  Hopefully, if there are murderes after all, they won't kill you.
Title: Re: A Liar And A Thief
Post by truemuffinman on Aug 24th, 2006, 4:47pm

on 08/24/06 at 00:05:46, Grimbal wrote:
Go and kill the thief.  You'll get the money back after you had a chance to fight him.  Being a murderer, the liar will stop lying to you.

The liar speaks 2 statements, both of them to the effect that the right road is deadly.  Unless he told the truth twice, which happens 1% of the time, that road is safe.
Tell the liar you are taking the left road and take the right one.  It makes you a liar.  Hopefully, if there are murderes after all, they won't kill you.

Never thought of that. Good job!
Title: Re: A Liar And A Thief
Post by Roy on Aug 25th, 2006, 8:04pm
Sameer's right.

There are logical answers, then there are the personal answers, me, i choose the thief. Not just because i value my life more than $500, but i know an actual magic trick which will multiply the next one dollar i make from doing nothing into two, then into five, then into ten, then into twenty, 50, 100 250, 500, so on. Or i would call Legolas ( i call him leg less  ;D )to check ahead on the liars path
Title: Re: A Liar And A Thief
Post by Sameer on Aug 26th, 2006, 11:09am
I like Grimbal's answers!!! especially the lying one.. least amount of work to fool everyone!!  ;D


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