You are standing at a crossroads that leads to two different doors: one leads to Heaven and the other to Hell. There are two gatekeepers—one standing in front of each door. One gatekeeper always tells the truth, and the other always lies, but you don’t know which is which. You are allowed to ask only one question to one of the gatekeepers to determine which door leads to Heaven.

Objective:
Figure out the question that will reveal which door leads to Heaven, ensuring you avoid Hell.

Solution

This classic puzzle is all about crafting a question that will give you the correct answer regardless of whether you ask the truth-teller or the liar. The key is to design a question that factors in the behavior of both gatekeepers.

Step-by-Step Solution for Heaven and Hell Puzzle:

Step 1: Understand the Gatekeepers' Behavior

• Gatekeeper A: Could either always tell the truth or always lie.
• Gatekeeper B: The other gatekeeper does the opposite of what Gatekeeper A does.

If you ask either gatekeeper what the other gatekeeper would say, the response will be deceptive:

• If you ask the truth-teller what the liar would say, the truth-teller will truthfully report the liar’s false answer.
• If you ask the liar what the truth-teller would say, the liar will lie about the truth-teller’s correct answer.

In both cases, the answer you get will be the wrong door.

Step 2: Formulate the Right Question

To determine the correct door, ask either gatekeeper the following question:

• “If I were to ask the other gatekeeper which door leads to Heaven, which door would they point to?”

This question works because:

• If you ask the truth-teller, they will truthfully tell you the door that the liar would falsely claim leads to Heaven (which is actually the door to Hell).
• If you ask the liar, they will lie about what the truth-teller would truthfully say, pointing you to the door to Hell as well.

In both cases, the gatekeeper will point to the door to Hell.

Step 3: Choose the Opposite Door

Once the gatekeeper points to a door, you should choose the opposite door. This door will be the one that leads to Heaven.

Final Answer

By asking, “If I were to ask the other gatekeeper which door leads to Heaven, which door would they point to?”, you can determine the door to Hell based on the response and then choose the opposite door, which will lead to Heaven.