Riddle of the Week

Riddle of the Week: The Hardest Logic Puzzle Ever

Difficulty level: Hardest Ever

By Jay Bennett
MICHAEL STILLWELL

Sailing through a thick fog, you come upon a mysterious island shrouded in mist. A towering volcano in the center of the island pierces the clouds, billowing smoke into the sky. You land your boat and set out to ascend the peak. After an arduous climb, you approach the volcano summit, where lava glows red within a vast crater.

Here, you are approached by three gods.


Problem

On the summit of this remote volcano, you realize a few things through divine intervention.

First, you know that one of the three gods always tells the truth, another always lies, and the third will respond to questions randomly. Therefore, let us call the gods True, False, and Random.

The gods speak a different language. They understand all languages perfectly well, but only answer questions with either ja or da, the words for yes and no. You do not know which god is which, and you do not know which word means yes and which word means no.

Finally, you have an existential problem on your hands. You may ask three yes-or-no questions, each one directed to only one god, and only that god will answer with either ja or da. If you can determine the identities of the three gods, they will send you on your way with their blessing, and you can be assured of a prosperous and fulfilled life. If you fail to determine the identities of the gods, however, they will be less generous in their treatment. The volcano pit smokes and glows red beside you.

With your three questions, how do you figure out which god is True, which is False, and which is Random?

Hint

To get to this island volcano with the three gods, we took a trip through other islands populated with knights and knaves. These previous encounters will give you the tools you need to identify the gods.

Solution

Check back Friday for the solution.