What's the answer to this riddle again?

[OUTLAWS 9.99repeating^32]

I'm trying to figure out a riddle. It's a very old and classic riddle and I was hoping that someone knows the answer.

Here is essentially how the riddle goes:

You are walking along a path, when you come across two brothers, both guarding a doorway behind them. One brother always tells the truth and the other brother always lies. One of the doorways leads to life and prosperity and the other doorway leads to death and misery. You are not sure which doorway is which. You are allowed to ask both of the brothers one question and one question only. What two questions do you ask to insure that you pick the door that leads to life and prosperity?

There are twists to this riddle, but the general premise remains the same. Does anyone know what question should be asked? I think it's something like "Does your brother always lie?"..but that is not correct because it would produce a "yes" answer from both of them and thus the second question wouldn't really help. The first question has to be a surefire way of separating the two brothers and identifying which one always lies and which one always tells the truth, but I'm not sure how to do it(if you know which one always tells the truth, you can ask him "Does the doorway behind you lead to life and prosperity?").

[Die Hard]

I don't know?

My tactic would be to blast both with the Shotty and take a look behind behind both doors.

However, to keep with the spirit in which it was posted. I'll have a think about it. :thumbs:

[Die Hard]

ok how about this:

Is your brother a liar? Answer....damn it that doesn't work! Ok later....

[OUTLAWS 9.99repeating^32]

Hmm...actually I think you only get one question to ask to one brother only..I'm not sure now.

[SALvation]

I think it's only one question to one brother.

[The Crimson Centurion]

if i were to ask your brother if that is the right door (good life)...would he say yes ..

no matter who you ask..the lie is propogated and the negative door (the one that is supposed to be bad) is always the good door...

:D

[JIMINATOR]

yep, tik has it right. would my brother say this is the correct door?
I recently read it in a sci-fi book, but couldn't figure it out either....

[Black Rose]

hmm I would just ask: Are you Rosie? :D
:p:

[JIMINATOR]

well, you have to guess the correct door, because the wrong one leads to death...

I wouldn't want that to happen to my sweet rose....

[OUTLAWS high ping camper]

*google search:
One possible solution is this: Ask one of them "If I had asked the other person if he always tells the truth, would he have said yes?" The truth-teller will answer yes to this question (the liar would have said yes if you had asked him if he was the truth-teller since he always lies), and the liar will answer no to this question (the truth-teller would have said yes as well if you had asked him if he was the truth-teller, but the liar would have lied and said no). Therefore, if the person you asked says yes, then he is the truth-teller and the other person is the liar, and if the person you ask says no, then he is the liar and the other person is the truth-teller.

[JIMINATOR]

the point is to use one question to one person to get to the correct portal..... that answer won't take you anywhere...

[OUTLAWS high ping camper]

the point is to use one question to one person to get to the correct portal..... that answer won't take you anywhere...

By using that one question, you will know which person is the liar. You will then know if you are talking to the liar or the truthful person when you ask them if they are standing in front of the "good" door. You are allowed to ask each brother one question, right?

[SALvation]

Nope. One question period.

[ME BIGGD01]

i am a bit confused because i read it and it says you can ask a question (1 question each) to the brothers. if that's the case i would ask 1 of them if they are brothers. the other brother i would ask which door leads to prosperity.

[OUTLAWS high ping camper]

Nope. One question period.

Ummm, not according to 9's first post:
What two questions do you ask to insure that you pick the door that leads to life and prosperity?

[OUTLAWS 9.99repeating^32]

Yeah I wrote the riddle incorrectly. I was just trying to describe the general idea and I did not realize how simple it is with two questions.

It may be impossible with only one question and without some other knowledge, like "the door behind the brother that always tells the truth leads to life". I'm sure that this is simple for someone who is entrigued by and enjoys reading and solving riddles, and I was hoping that there would be at least one person like that on this board.

Thanks everyone for your replies.

[Oscar(WCFD)]

You ask one of the brothers "If I were to ask your brother which door leads to life and prosperity , what would he say". And then you pick the opposite door of what he tells you.

so if you ask the brother that lies he would say that his door leads to life and prosperity , if you ask the brother that tells the truth he would tell you that his brother would say that his(the lier) door leads life and prosperity.

no matter who you ask the answer always points to the lier, so you pick the opposite door. :confused:

now I've got a headache ;)

[OUTLAWS 9.99repeating^32]

You ask one of the brothers "If I were to ask your brother which door leads to life and prosperity , what would he say". And then you pick the opposite door of what he tells you.



Yeap, that's correct! Thanks Oscar!

[JIMINATOR]

uh, that was pretty much the same answer tik and i gave.... :wacko:

[ME BIGGD01]

that does not prove anything because if you ask the brother who lies, he will still give you false info. and how do you know who is the honest and the liar? i think the riddle is flawed with no conclusion.:confused:

[Black Rose]

well, you have to guess the correct door, because the wrong one leads to death...

I wouldn't want that to happen to my sweet rose....
hmm why jimhoneybunny? :wub:
We have two brothers here: Liar-Jon and Truthteller-Tony.

1. Question: Are you Rosie?
- I ask Liar-Jon: His answer has to be yes, because he always lies.
- I ask Truthteller-Tony: His answer has to be no, because he never lies.

So with that question I know which one of them is the liar.

2. Question: depends on who is the liar and finally left for another question:

Situation a: First question "are you Rosie" goes to the brother standing left at the crossroad. He sais "yes" -----> I know it is Liar-Jon. :)
second question to the brother right at the crossroad who always tells the truth: Is the way behind you leading to life?

Situation b: First question "are you Rosie" goes to brother who sais "no".
I know he is Truthteller-Tony.
So my second question is for Liar-Jon: Is the way behind you leading to life? He will lie an I will take the other way :)

Maybe I am wrong but I still think this can work :)

[JIMINATOR]

ah, but you only get one question to one brother to determine the door...

[Black Rose]

ah, but you only get one question to one brother to determine the door...
oh, I thought two. Well in that case Tik is right...... and you :p:

[Die Hard]

do not compute, do not compute :confused:

[Die Hard]

Is this out of a Laurel & Hardy sketch?

[OUTLAWS 9.99repeating^32]

uh, that was pretty much the same answer tik and i gave.... :wacko:

Yeah..looking back I see that you guys gave essentially the same answer..but for some reason it didn't register as correct with me at the time; so sorry for not saying thank you earlier. Thank you Jim and TCC!

And for those that still do not understand, re-read this sentance:

You ask one of the brothers "If I were to ask your brother which door leads to life and prosperity , what would he say". And then you pick the opposite door of what he tells you.


Let's call the door that leads to life the "White" door and the door that leads to death the "Black" door for simplification.

Now, let's say that we ask the brother that always tells the truth first, just by luck. Ok, so we ask him what his brother would say(the one who lies) if we asked him which door is the white door. This brother does not lie, but his other brother does lie. So this brother that always tells the truth will tell us which door the lying brother would say it is, which is actually the black door. We do not want the black door, so we pick the opposite door that the honest brother told us.

Conversely, let's say that we ask the brother that always lies. We ask him what his brother would say(the one that tellls the truth) if we asked him which door is the white door. Remember, this brother always lies. This lying brother knows that the honest brother would pick the correct white door, but he always lies and thus tells us the incorrect door. We do not want the black door, so we pick the opposite door that the lying brother told us.

Either way, you ask the question, "If I were to ask your brother which door leads to life and prosperity , what would he say", and simply pick the other door. I hope that clarified the riddle somewhat.

[The Crimson Centurion]

oh, I thought two. Well in that case Tik is right...... and you :p:


I'm not TIK :p

and of course I'm right :p



;)

[Death Engineer]

You go to either guard at door A. You ask him would the OTHER
guard tell you to take his door, door A. If he says yes,
take door B. If he says no, take door A.

[Slice]

Or you could just say, If this is the right door open it and go first.

[solid snake295]

lol, Slice, that would work if you made it a question.

you would have to say somthing like "what color is the door knob on the other side of that door?"

if he dosent come back, pick the other door. :p: