Logic excersice: Heaven and Hell

[dustin_archibald]

Here's another one to pump up that brain power...

Heaven and Hell
You die and find yourself driving in a '57 Chevy down a gravel road. Soon, or not soon enough, you come to a T intersection with a booth smack dab in the middle of it and two little grey beings inside. You, being the inquisitive person that you are, get out and read the sign nailed to the wall:

--
Welcome!
You've reached the cross-roads of Limbo!
One road leads to Heaven. One road leads to Hell (bwah ha ha ha ha ha!).
When you push the red button one of the little grey things inside will come out; both know the direction to Heaven; both know the direction to Hell. Here are the rules:

1. Once you pick a road there's no coming back.
2. One of the grey things only tells the Truth. The other tells only Lies.
3. You may only ask the thing that comes out one (1) question.
4. You only get one shot at this so make it count. You can't ask the other one any questions.
5. If you take too long they will laugh at you. Both of them. I don't think you'll enjoy it.

Thanks and have a groovy afterlife!

-The One True General Overseer Director
--

You want to get to Heaven so what do you do?

[Guille]

As I've long known the answer to this problem (but in a different form) I won't post it. It's pretty easy, you jsut need to make a small diagram with the possibilitief asking each of them weather what they say is true or false, you'll find one of the possibilities tells you what to do.

[zeroca]

I don’t think this easy task has a solution (i.e. solution, which gives you right answer in 100% cases), because question, you offer always consists of two parts that are united artificially:
For instance you pick any of two roads and ask gray thing, who comes out:
If I asked whether this road is to the heaven, would you answer yes?
---if the road is picked right, both of them say yes;
---if the road is picked wrong, both of them say no.
But the matter is that the 3.condition of task obliges you to ask only one question, but not the question that consists of two independent questions.

[zeroca]

I’ll offer better example and once again from the childhood:
Two bandits caught you and are thrusting the knife under your ribs:
1. You must say something quickly in order to stop them and when you utter even a single word, they will stop at once.
2. If the word or sentence you said is right, they will shoot you;
3. If the word or sentence is wrong, they will hang you.
How would you survive, Dustin?

[dustin_archibald]

I don’t think this easy task has a solution (i.e. solution, which gives you right answer in 100% cases), because question, you offer always consists of two parts that are united artificially:
For instance you pick any of two roads and ask gray thing, who comes out:
If I asked whether this road is to the heaven, would you answer yes?
---if the road is picked right, both of them say yes;
---if the road is picked wrong, both of them say no.
But the matter is that the 3.condition of task obliges you to ask only one question, but not the question that consists of two independent questions.

The task has a solution that works 100% of the time. Although it takes some working through.

[dustin_archibald]

I’ll offer better example and once again from the childhood:
Two bandits caught you and are thrusting the knife under your ribs:
1. You must say something quickly in order to stop them and when you utter even a single word, they will stop at once.
2. If the word or sentence you said is right, they will shoot you;
3. If the word or sentence is wrong, they will hang you.
How would you survive, Dustin?

I would yell, "Stop!"

My reasoning is that I didn't say "right" and I didn't say "wrong" so they won't kill me. If I said "right" or "wrong" they would dispatch me with the methods described above.

[zeroca]

I would yell, "Stop!"
My reasoning is that I didn't say "right" and I didn't say "wrong" so they won't kill me. If I said "right" or "wrong" they would dispatch me with the methods described above.

No, my friend, you should cry:” you’ll hang me", so if they decide to hang you, it will turn out to be true and in this case they must shoot you, but if they decide to shoot you, it will turn out to be wrong, so they must hang you. But if you cry “stop!” they will firstly stop, then shoot and hang you, or vice-versa.

The task has a solution that works 100% of the time. Although it takes some working through.

I solved it when I was a child, but I repeat, there are several variants to solve this task, and the only way is to ask a question, which consists of two parts, artificially united so, as if it were one question. My variant I already showed:
You pick any of two roads and ask gray thing that comes out:
“If I asked whether this road is to the heaven, would you answer yes”?
---if the road is picked right, both of them say yes (i.e. if gray thing happened to be honest, he would say yes and so on your question also answers positively, but if gray thing is a liar, so he would answer no, but he lies the second time and answers yes in contradiction of his real would be answer);
---if the road is picked wrong, both of them say no, so you identify both roads.
But the question in bold consists of two questions, so isn’t one question.
Can you offer your variant?

[dustin_archibald]

No, my friend, you should cry:” you’ll hang me", so if they decide to hang you, it will turn out to be true and in this case they must shoot you, but if they decide to shoot you, it will turn out to be wrong, so they must hang you. But if you cry “stop!” they will firstly stop, then shoot and hang you, or vice-versa.

Ah, I see. I thought it was a play on words but it was a logic problem.

I solved it when I was a child, but I repeat, there are several variants to solve this task, and the only way is to ask a question, which consists of two parts, artificially united so, as if it were one question. My variant I already showed:
You pick any of two roads and ask gray thing that comes out:
“If I asked whether this road is to the heaven, would you answer yes”?
---if the road is picked right, both of them say yes (i.e. if gray thing happened to be honest, he would say yes and so on your question also answers positively, but if gray thing is a liar, so he would answer no, but he lies the second time and answers yes in contradiction of his real would be answer);
---if the road is picked wrong, both of them say no, so you identify both roads.
But the question in bold consists of two questions, so isn’t one question.
Can you offer your variant?

Hopefully anyone else who reads this won't be disappointed that I posted this answer:

When the grey thing comes out ask, "If I were to ask that other grey thing which is the road to Heaven which road would it tell me to take?". When it answers take the other road (go in the opposite direction).

Case 1: The grey thing you are talking to always tells the Truth
The other one (in the booth) would tell you to take the road which leads to Hell if you asked it which road went to Heaven (it always Lies). Since the one you are talking to always tells the Truth (remember the question you asked it) it will tell you to take the road the other grey thing would tell you to take, which is to Hell. Take the opposite, the other road, and you go to Heaven.

Case 2: The grey thing you are talking to always tells Lies
The other one (in the booth) would tell you to take the road which leads to Heaven if you asked it which road went to Heaven (it always tells the Truth). Since the one you are talking to always Lies (remember the question you asked it) it will tell you to take the road opposite to the one the other grey thing would tell you to take, which is to Hell. Take the opposite road, the other road, and you go to Heaven.

[michellemfry]

You go to heaven. Ignore the whole thing. Heaven is up, not down a road somewhere. Your guide will be along shortly to transport you away from such foolishness.

Trust me. I'm older than dirt.

[TinyTree]

If I asked the other guy which road to hell, which road would he say?


The guy who tells the truth would point to heaven. The guys who lies would point to heaven.