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Wizard
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Wizard
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December 18th, 2025 at 7:48:54 PM permalink
I usually post logic and math puzzles in the Easy Math Puzzles thread, but this one merits its own. Here is the Wikipedia wording:

Quote:

Three gods A, B, and C are called, in no particular order, True, False, and Random. True always speaks truly, False always speaks falsely, but whether Random speaks truly or falsely is a completely random matter. Your task is to determine the identities of A, B, and C by asking three yes–no questions; each question must be put to exactly one god. The gods understand English, but will answer all questions in their own language, in which the words for yes and no are da and ja, in some order. You do not know which word means which.



I hesitate to give a link because it explains an answer.

I'd add to that wording you can't ask the true or false god a paradoxical question. The random god will not even listen to the question but answer "yes" or "no" randomly when you fishing speaking.

An easier version of this has recently been asked in the Easy Math Puzzles thread, in which the question of language was omitted.

There are many possible solutions.

The question for the poll is what are your thoughts?
"My life is spent in one long effort to escape from the commonplace of existence. These little problems help me to do so." -- Sherlock Holmes
ThatDonGuy
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December 19th, 2025 at 6:56:18 AM permalink
Where's the box for "I've seen harder logic puzzles"?

The hardest one I can think of is The Riddle of Dracula, in Raymond Smullyan's book What Is the Name of This Book?
Wizard
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Wizard
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December 20th, 2025 at 2:45:59 PM permalink
Sorry to see this problem didn't get much traction. I have been working on it for days. Here is my 9-page solution (PDF).

Care to share this Dracula riddle?
"My life is spent in one long effort to escape from the commonplace of existence. These little problems help me to do so." -- Sherlock Holmes
AutomaticMonkey
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December 20th, 2025 at 5:09:42 PM permalink
Quote: Wizard

Sorry to see this problem didn't get much traction. I have been working on it for days. Here is my 9-page solution (PDF).

Care to share this Dracula riddle?
link to original post



I think its requiring 9 pages and days (and for you, who probably work more concisely than most of us) might be the reason! Reminds me of exams I took where you will fill up a blue book with each derivation.

With puzzles like that it's never clear to me how many logical elements I can have per question, and how to phrase them in English and not Boolean notation. Like: "If I were to ask god A if god C is a liar, and da means yes in English, or if you answer randomly, would his answer allow me to eliminate two possibilities for the solution?"
ThatDonGuy
ThatDonGuy
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December 20th, 2025 at 5:34:00 PM permalink
Quote: Wizard

Care to share this Dracula riddle?
link to original post


Since it's in a book that is still in print, I don't feel it's right to break the author's copyright on it.
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