You probably heard this one but i dont know the...

Originally posted by AThousandYoung
Tiger, I don't think your answer works. Can you explain further?

I say: "Please point to a door that you could have pointed to yesterday if I had come along and asked you to point to a door that led to heaven"

Truth teller thinks => "Well, yesterday I could have only pointed to the heaven door in answer to that question, so now I shall indicate that"
He points to the heaven door.

Liar Thinks => "Well, yesterday I would have lied and could have pointed to any of the non-heaven doors, but now I must lie about that, I shall indicate the heaven door as that is the only door I couldn't have pointed to yesterday".
He points to the heaven door.

Originally posted by iamatiger
I say: "Please point to a door that you could have pointed to yesterday if I had come along and asked you to point to a door that led to heaven"

Truth teller thinks => "Well, yesterday I could have only pointed to the heaven door in answer to that question, so now I shall indicate that"
He points to the heaven door.

Liar Thinks => "Well, yester ...[text shortened]... as that is the only door I couldn't have pointed to yesterday".
He points to the heaven door.

Got it. Thanks.

Originally posted by iamatiger
Ah - so by "Brother" you mean "Someone opposite to yourself"? That would indeed work. Congratulations!

The way I have seen problems like this phrased is 'There are identical twin brothers who
are alike in every way except in one respect: one always tells the truth, and the other
always lies.'

This is what I was thinking.

Originally posted by iamatiger
I say: "Please point to a door that you could have pointed to yesterday if I had come along and asked you to point to a door that led to heaven"

Truth teller thinks => "Well, yesterday I could have only pointed to the heaven door in answer to that question, so now I shall indicate that"
He points to the heaven door.

Liar Thinks => "Well, yester ...[text shortened]... as that is the only door I couldn't have pointed to yesterday".
He points to the heaven door.

It's the same manner of negation, just a different medium.

Originally posted by Nemesio
Originally posted by iamatiger
[b]Ah - so by "Brother" you mean "Someone opposite to yourself"? That would indeed work. Congratulations!

The way I have seen problems like this phrased is 'There are identical twin brothers who
are alike in every way except in one respect: one always tells the truth, and the other
always lies.'

This is what I was thinking.[/b]

Yes- but i was just pointing out that the problem is equally solvable if you have just one person to ask, who speaks a different language to you, and there are infinite number of doors. It is amazing how easy the classic version of the problem makes it.

Originally posted by bloodyboy
i heard this in 5th grade and now in 9th is still dont know the answer so can you tell me. ok here it is... two guys are in a room wearing the same thing, one lies the other tells the truth. there are also two doors and one leds to heaven and the other to heck. you want to know which leds to heaven. you CAN ONLY ASK ONE question to ask both the people to find out which is heaven or heck, what is the question? and i dont know the answer.

for pete's sake! just ask them which door leads to heaven! it's that simple!