There are 2 doors, one leads to heaven one leads to hell. There are 2 identical twins one always tells the truth and one always lies, if you could only ask one question to know 100% which door leads to where what would you ask

"Which door would your twin say leads to heaven?"

Take the other door.

(This is assuming that the twins know that the other twin always lies/tells the truth)

Quote:

---

smearcase disagrees: What if you are talking to the truthful twin?

---

Then he would say that his twin would say the door to hell, in which case you still take the other door.

In either case, they will indicate the door that leads to hell.

If I had asked you yesterday,which door would you have told me to take to get to heaven?

They both have to say the same correct door, because the liar had to lie yesterday and has to tell you the opposite of his lie from yesterday.

Capuchin--My apologies. I misread your plan of attack there.
In fact, I like your answer better because the logic is so concise (in spite of the fact that I couldn't read it right the first time!).

Quote:

---

Originally Posted by smearcase

Capuchin--My apologies. I misread your plan of attack there.
In fact, I like your answer better because the logic is so concise (in spite of the fact that I couldn't read it right the first time!).

---

But mine has the ugly assumption that the twins know what the other will say! I like yours better!