What is the answer to this riddle?

Let me explain why the liar could answer the question posed by MOU could be answered as "He would say to eat a mushroom."

You ask the liar the following question, as MOU suggests: "If I would ask your brother, what would he say which door lead to safety?"

The liar would reason as follows: If you asked my brother, the truthteller, which door leads to safety, he would say "that door there is the door to safety". So it would be a lie that the truthteller would say "Eat a mushroom". It would also be a lie that the truthteller would say "Go in that door (which I know to be the door of death)"

The liar can pick either of these statements as a lie as to what the truthteller would actually say. Since he can pick either of these statements and still be lying, why not pick the answer that is a lie and won't be of any help to you in figuring out which door to open?

What if both tell the truth, but one is sprawled out on the floor like a dog?

Pedro, as I already said - you can ask each brother same question.
So it doesn't matter what will liar say.
Let's say right door is A
In that case if you ask "what would your brother say....." truth teller will say "B" because he can't guess that liar will say "mushroom".

So, you will either have "B" and "B" answers
Or: "B" and "mushroom" answers.
And you have to choose A

Or you can just eat alphabet soup while the guards starve.

MOU said:

If truthteller can't guess what liar might say, then the only answer the truthteller can give to this question is "I don't know." If he says "door A" then he would be lying.

Therefore, you will now have to choose between the 2 answers of "I don't know what my brother what say, there is no way for me to predict it." and "My brother would say to eat a mushroom."

okay, if you insist, then just rephrase and ask "Is it possible that your brother would tell me that right door is A if I asked him?"

If A actually IS right door, then truth teller will answer "no" (because IT IS possible), and liar will say "no", "mushroom", "emergency personal", "chicken soup", or "Danish soccer team" - anything but "yes", because in that case he would tell truth.

If A is NOT right door - then truth teller will answer "yes" (because in that case it's possible that liar would say "yes", as well as it's possible that he would say "basketball", "Egypt", or "Leonardo Di Caprio", but he would never say "no"), and liar would say either "yes" or "Michigan", "corn fields" or "Hundred years of solitude".

In each case you choose opposite - if you have one or two answers "yes" then choose B, if you have one or two answers "no" then choose A.

With that question, however, with all twists and possibilities, you will CERTAINLY have at least one answer that is about the doors and not about mushrooms.

Finally, you have come up with one of the correct questions you can ask the 2 guards.

And actually, the liar could not answer the question as "Mushroom" or "Apple" etc because that would be a nonsensical answer, not a lie. It was only a lie with the other questions before because you were asking him what someone else would say, so as as long as he offerred a statement the other person would not say, it would be a lie. Here he has to answer "yes", "no" or "I don't know" in order to make his answer a lie.

By the way, the key difference with this puzzle, and the classic way it is given, is that here, the riddle is stating you get to ask each one a question.

If you only get to ask one question, then if you ask the liar, he could just answer the question as "I don't know" which is a lie because really he does know, and now you are screwed.

Can anyone think of a one-question-only answer to the riddle? (You don't know if you are asking the liar or the truth teller.)

It's not possible since we don't know whether the guards know which way to go. It is possible, no matter how well we word our two questions, that they do not.

If we guess we have a fifty percent chance of picking the correct door. I think we should at least focus on improving that probability.

if we assume that guard does know which door is right then: (english grammar alert!) you can ask something like: "If another guard was there and his truth-worthiness would be exactly opposite then yours, what would he say which door is right?"

Again, you choose other one.

Of course, you could get in touch with your death relatives who, in turn, could allow you to communicate with Death. Death would then tell you which room he frequented the most and you would thank him, offer him some lunch some time, and steer clear of that room.

Simple as cheese.

Oh! I got it figured out. One of the guards must be Death. And the other guardian must be an angel. I think I'm starting to catch on.

Just look for ivory and feathers.

But that makes death a liar, which is probably how he wins at poker so often. And gambling with death is no laughing matter (cause that constant smile is really scary). Ohhh....

Ask both: "If you were the other guard, who would you say was the the truthful one?"

Lier: "I would say he was."

Truthful: "I would say I was."

Because: if the lier was the truthtful one, he would say "I would say I was." But since he is a lier, he would say "I would say he was."
If the truthful one was the lier, he would say "I would say I was." And since he tells only the truth, he must be the truthful one.

&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbspBut then you've just wasted your only question trying to figure out who tells the truth. The objective is to come up with a foolproof question that will guarantee you safe passage.

If you want to waste your question finding out who is the liar you could just ask both "What color is the ceiling?" You don't need to be tricky.

the True answer
Actually, the correct answer would be as follows: The fact that there are two is a red herring - you only need one of either type. You ask him the following question: "If I were to ask you if the left door leads to freedom, would you say 'yes'?" If the person asked is a truth teller, he will answer "yes" if the left door leads to freedom, and "no" otherwise. But so will the liar. So, either way, go left if the answer is "yes", and right otherwise.

crdshrk007

And what would you do if the guard (who happens to be the truthteller) answers you "No" because he would actually have told you "absolutely" which is not the same as "yes"? You would go right, which means you are dead...

Or what would you do if the guard (who happens to be the liarr) answers you "I don't know" because he really does know what he would say, so "I don't know" would be a lie?

There is a Most Simple solution:

The man Should ask:

"Which door would the other gaurd tell me to take, if I asked him the way to freedom"


If you ask the truth teller, he'll say the other gaurd would lead you to the death door, and would point at the death door
If you ask the liar, he would say that the truth teller would point you in the wrong direction and would also point at the death door

So You would just take the other door. Special Thanks to my Friend Chuck Soon to be Ruler of the World!