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Iraq11

Difficult Riddle!

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:D

 

A Muslim M enters a room with 5 doors. One of the doors will lead him to his brothers and sisters in Islam and the other 4 will lead him to enemies of Islam.

 

In the middle of the room, there are 5 people lined up in a single line, numbered 1 to 5. These people are either hypocrites (liers) or truthful (trustworthy), but a person have to tell the truth if the person before it lies and vice versa. For example, if person 1 is a lier, person 2 is truthful.

 

The Muslim M does not know anything else about the 5 persons. Also, he cannot ask a direct question to find out if a stone is lying or not. For example, he cannot go up to person 1 and ask if 1 + 1 is equal to 2.

 

The Muslim M can ask only up to one question per person and M cannot go backwards in the questionings. For example, if M asks person 4, he cannot ask person 3, 2, or 1.

 

 

How does M lead himself to safety (with his brothers and sisters)?

 

 

:D

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PropellerAds
Does he know how many are liers and how many are truthful?

What he knows is :

- Either: 3 are liers and 2 are truthful

- or: 2 are liers and 3 are truthful

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What he knows is :

- Either: 3 are liers and 2 are truthful

- or: 2 are liers and 3 are truthful

 

 

I think I know the answer, would you like me to say or is it better to wait and see if others guess?

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I think I know the answer, would you like me to say or is it better to wait and see if others guess?

I think it's better that you wait a bit to see if other members try to get the answer...

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Stand in the first position and be truthful :D

 

I really dont know what the answer is. I wait for some else to answer

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What he knows is :

- Either: 3 are liers and 2 are truthful

- or: 2 are liers and 3 are truthful

 

:D

 

ok i thought i knew the answer, but i'm not so sure now... :D

 

hmmm....

Edited by freedslave

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:D

 

bro Iraq11...can this be solved by logic, or is there another way?

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:D i thought i knew this, but with the choice of 2 doors and 2 people but i can't figure it out with this one.

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What would the other person answer if I asked: "Are you a liar?"

 

If the first answers: No then that means the first person is truthful.

If the first answers: Yes then that means the first person is liar.

 

Then you can ask the next people which door is the safe one...

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:D

 

bro Iraq11...can this be solved by logic, or is there another way?

It can be solved by logic and intelligence, brother. There is no "trick" behind it.

 

 

What would the other person answer if I asked: "Are you a liar?"

 

If the first answers: No then that means the first person is truthful.

If the first answers: Yes then that means the first person is liar.

 

Then you can ask the next people which door is the safe one...

Although it is not the solution I know, this seems to be a good start, Liberté. Could you please detail your answer, and remember that you can ask at most 4 questions!

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Well in with my method I will either know that the first person is a liar or a truthful person. So if he is a liar I just have to ask the next one along which door is safe, and if he i truthful I ask the person after next which door is safe.

 

Isn't that it?

Edited by Liberté

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Well in with my method I will either know that the first person is a liar or a truthful person. So if he is a liar I just have to ask the next one along which door is safe, and if he i truthful I ask the person after next which door is safe.

 

Isn't that it?

But the five persons can only say "Yes" or "No" (maybe I forgot to mention it in the riddle's description, sorry). So if person1 is a liar then you ask person2 (a truthful in this case) "which door is safe", what will be his answer: 'Yes' or 'No'? Same applies if person1 is truthful...

An answer with 'Yes' or 'No' is not compatible with a question beginning with 'which'.

 

Nice try Liberté, but it doesn't solve the riddle!

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But the five persons can only say "Yes" or "No" (maybe I forgot to mention it in the riddle's description, sorry). So if person1 is a liar then you ask person2 (a truthful in this case) "which door is safe", what will be his answer: 'Yes' or 'No'? Same applies if person1 is truthful...

An answer with 'Yes' or 'No' is not compatible with a question beginning with 'which'.

 

Nice try Liberté, but it doesn't solve the riddle!

 

I don't think you made it a condition that the questions had to be answered with a Yes or No, but I should have guessed!

 

So...

 

Since we now know which person is truthful or a liar (by establishing which of the 2 the first person was).

 

We can ask the second person (P2) if door 1 (D1) is the one we want.

If the first person is truthful, then this person must be a liar so if he says YES then we know it isn't. If he says NO then we know it is and the problem is solved.

If the first person is a liar, then this person must be truthful so if he says NO then we know it isn't. If he says YES then we know it is and the problem is solved.

 

We can do the same to the remaining three people, each time either finding the correct door or eliminating one. So by the last person we have either found the door, or elimated 4 of them.

 

Problem solved?

Edited by Liberté

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Salaams

just ask the first 4 people which door leads to Islam.

the order can either be

t,f,t,f

or

f,t,f,t

either the lies will be insynch or they won't be in synch

If they are not in synch, then there is your answer.

ex. people may say:

door 1, door,3, door1, door 4

so obviously door 1 is it.

 

IF they are in synch like

door1,door2,door1,door2

then

then just ask the last person if door 3 is it.

if the person answers yes then he is lieing bcaz it has to be either

door1 or door 2.

If the person says no, then he is not lieing thus the

person before him must be lieng...

so if the person before him said door2, the answer will be door 1

:D ?

Edited by llogical

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Salaams

just ask the first 4 people which door leads to Islam.

the order can either be

t,f,t,f

or

f,t,f,t

either the lies will be insynch or they won't be in synch

If they are not in synch, then there is your answer.

ex. people may say:

door 1, door,3, door1, door 4

so obviously door 1 is it.

 

IF they are in synch like

door1,door2,door1,door2

then

then just ask the last person if door 3 is it.

if the person answers yes then he is lieing bcaz it has to be either

door1 or door 2.

If the person says no, then he is not lieing thus the

person before him must be lieng...

so if the person before him said door2, the answer will be door 1

:D ?

Thank you llogical for your logical answer. But, as I said to Liberté, the 5 persons can only say "Yes" or "No". Can you please modify your answer so that it takes this condition into consideration?

 

 

 

 

 

I don't think you made it a condition that the questions had to be answered with a Yes or No, but I should have guessed!

 

So...

 

Since we now know which person is truthful or a liar (by establishing which of the 2 the first person was).

 

We can ask the second person (P2) if door 1 (D1) is the one we want.

If the first person is truthful, then this person must be a liar so if he says YES then we know it isn't. If he says NO then we know it is and the problem is solved.

If the first person is a liar, then this person must be truthful so if he says NO then we know it isn't. If he says YES then we know it is and the problem is solved.

 

We can do the same to the remaining three people, each time either finding the correct door or eliminating one. So by the last person we have either found the door, or elimated 4 of them.

 

Problem solved?

You are very close to the solution, Liberté. However, you didn't solve the problem, you know why?

Let's count how many questions you need to ask (in a worst case scenario) using your method:

 

 

Since we now know which person is truthful or a liar (by establishing which of the 2 the first person was).

This was one.

 

 

 

 

We can ask the second person (P2) if door 1 (D1) is the one we want.

That was question number two.

 

 

 

 

If the first person is truthful, then this person must be a liar so if he says YES then we know it isn't. If he says NO then we know it is and the problem is solved.

If the first person is a liar, then this person must be truthful so if he says NO then we know it isn't. If he says YES then we know it is and the problem is solved.

Since the two cases are symetrical, let's suppose p1 is truthful and therefore p2 is liar.

Remember, Liberté, that you have asked 2 questions and therefore you have at most 2 other remaining questions.

 

 

 

 

 

We can do the same to the remaining three people, each time either finding the correct door or eliminating one. So by the last person we have either found the door, or elimated 4 of them.

You have only 2 remaining questions:

Question n°3: you ask p3 (truthful, using my supposition) if d2 leads to Islam. If he says "Yes" you win, else you go to next step.

Question n°4: you ask p4 (liar) if d3 leads to Islam. If he answers "No" you win. If he says "Yes", you will know for sure that either d4 or d5 lead to Islam, but there is no "next step" because you have consumed your 4 questions...

So which one, d4 or d5? You can't know...

 

 

 

 

 

Problem solved?

Not yet!!

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:D

 

Wow this is becoming complicated... :D

Brother Iraq11, just to clarify...if there are 5 persons how come we only get to ask 4 questions?

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:D

 

Wow this is becoming complicated... :D

Brother Iraq11, just to clarify...if there are 5 persons how come we only get to ask 4 questions?

 

The Muslim M can ask only up to one question per person

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Salaams

Thank you llogical for your logical answer. But, as I said to Liberté, the 5 persons can only say "Yes" or "No". Can you please modify your answer so that it takes this condition into consideration?

coolbeans :D

first off, I'm assuming that we are not allowed to actually check the doors? :D bcaz that would make it too easy. :D

Now b4 I try to put my answer in boolean format, there are totall of 5 doors including the

one that M enters from?

Because If so then we have totall of 4 doors to choose from

and the format can only be

TFTF or FTFT

But if there are 6 doors then it has to be

tftft or ftftf

lemme know which condition applies b4 I go further? :D

Peace

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:D

 

Looking at Liberté's question "Are you a liar?" how would you know that the person is telling the truth if he answers NO? I understand that if he answers YES, then he's definitely a liar, because he could be lying about the fact that he's a liar....But if he answers NO, then can't he be lying?

 

I'm confused...:D

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:D

 

Looking at Liberté's question "Are you a liar?" how would you know that the person is telling the truth if he answers NO? I understand that if he answers YES, then he's definitely a liar, because he could be lying about the fact that he's a liar....But if he answers NO, then can't he be lying?

 

I'm confused...:D

 

The question I would ask the first person would be:

 

"If I asked the second person if they were a liar what would they say?"

 

If the first person is a liar then the second person is honest so the answer would be YES.

If the first person is honest then the second person is a liar so the answer would be NO.

 

In this way we can work out the order of the liars and honest people.

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:D

 

Wow this is becoming complicated... :D

Brother Iraq11, just to clarify...if there are 5 persons how come we only get to ask 4 questions?

That's the difficulty of the problem, brother freedslave. If we had 5 questions, it would have been easy! One out the 5 persons will not be asked.

And as brother hkrespect mentioned, we can ask only one question per person (total 4 questions maximum).

 

 

 

 

 

Salaams

 

coolbeans :D

first off, I'm assuming that we are not allowed to actually check the doors? :D bcaz that would make it too easy. :D

Now b4 I try to put my answer in boolean format, there are totall of 5 doors including the

one that M enters from?

Because If so then we have totall of 4 doors to choose from

and the format can only be

TFTF or FTFT

But if there are 6 doors then it has to be

tftft or ftftf

lemme know which condition applies b4 I go further? :D

Peace

We do not take what M entered from into consideration. There are 5 distinct doors apart from where he entered (using your terminology, there are 6 doors).

 

 

 

And still no one has solved the problem yet!!

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The question I would ask the first person would be:

 

"If I asked the second person if they were a liar what would they say?"

 

If the first person is a liar then the second person is honest so the answer would be YES.

If the first person is honest then the second person is a liar so the answer would be NO.

 

In this way we can work out the order of the liars and honest people.

ooooh I see...I initially misread the question...alright, that makes sense.

 

But this is quite a difficult riddle indeed... :D

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There are five people so we have 5 questions right?

 

In which case my method establishes whether the first person is truthful T or a liar L.

 

Ask the second person if D1 (door1) is the one we want, since we know if he is T or F we can either choose or eliminate this door.

 

Ask the third person if D2 is the one we want, since we know if he is T or F we can either choose or eliminate this door.

 

Ask the fourth person if D3 is the one we want, since we know if he is T or F we can either choose or eliminate this door.

 

Ask the fifth person if D4 is the one we want, since we know if he is T or F we can either choose or eliminate this door.

 

Now we have asked 5 questions and we have either gotten the right door or we have eliminated 4 of them. I don't understand why this isn't correct!

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