close
Advertisement
Magazine
 

The Puzzle Dubbed The Hardest Ever By A University Professor

The Harvard Business Review may have published this logic puzzle back in 1996, but people are still scratching their heads over it today. 

The Puzzle Dubbed The Hardest Ever By A University Professor
Pixabay
The Puzzle Dubbed The Hardest Ever By A University Professor

Are you itching to test your smarts? You’ve come to the right place. The Harvard Business Review may have published this logic puzzle back in 1996, but people are still scratching their heads over it today. 

Mathematician Richard Smullyan, nicknamed “the undisputed master of logical puzzles” by former PhD student Bruce Horowitz, really outdid himself with this brainteaser.

As a matter of fact, Smullyan’s colleague, an MIT logic professor named George Boolos, called it “the Hardest Logic Puzzle Ever”—and we can see why.

Here is the riddle, straight from the mathematician’s mouth:

“Three gods, A, B, and C, are called, in some order, True, False, and Random.

True always speaks truly,

False always speaks falsely, but whether Random speaks truly or falsely is completely random.

You must determine the identities of A, B, and C by asking three yes-or-no questions, and each question must be posed to exactly one god.

The gods understand English, but will answer all questions in their own language. In their unknown language, the words for “yes” and “no” are “da” and “ja,” in some order. You do not know which word means which.”

So, which questions would you ask to identify each god? And no, it’s not a trick question. As a matter of fact, there are multiple ways to get the correct answer.

We’re willing to bet that your brain feels pretty busted at this point. If you’re ready to throw in the towel and hear the solution, we won’t tell! Here are the three questions you should ask, according to Nautilus:

1. To god A: “Does ‘da’ mean ‘yes’ if and only if you are True and if and only if B is Random?” (We supposed A said, “ja,” making B True or False).

2. To god B: “Does “da” mean ‘yes’ if and only if Pluto is a dwarf planet?” (We supposed B said, “da,” making B True.)

3. And to god B (True) again: “Does ‘da’ mean ‘yes’ if and only if A is Random?” Since B’s True, he must say “da,” which means A is Random, leaving C to be False.

Don’t beat yourself up if you’re still a little confused. You can start sorting out the solution with this 2008 paper, which claims to have the easiest answer to the brainteaser. 



How Do You Make Those Tough Life Decisions?

How Do You Make Those Tough Life Decisions?

Too often, when faced with a fork in the road - whether picking up and moving cross-country or having a child - we fret and dither so long that choice is no longer an option.
How To Think Big And Realise Your Goals

How To Think Big And Realise Your Goals

How do you reach a goal, change your life, realise a dream? If you delve into the backstories of successful people, a common theme emerges: They think big.
8 People with Higher IQs Than Einstein

Think Einstein Was Smart? Here Are 8 People with Higher IQs

The average IQ is 100, and an IQ of 140 is considered genius.
 12 Optical Illusions That Will Make Your Brain Hurt

12 Mindbending Optical Illusions That May Break Your Brain

From spinning circles to disappearing dots, these insane optical illusions aren't what they appear to be.
Advertisement