Puzzle - how to ensure you get the quarter, not the penny


Originally published at: https://boingboing.net/2018/11/12/puzzle-how-to-ensure-you-get.html


Hey, I’m getting better at these! I got it right away!

…ummm. Carry on?



Ha, I got it right away, too, which must mean it is way easier than most Futility Closet puzzles.


You will retain the penny.


That statement is false because I’m going to throw the penny into a nearby trash can or body of water. I won’t retain it, but neither will I give it to you. Therefore I don’t have to give you either coin.


“The penny may be covered in a deadly poison.”


Only problem there (duh) is that any statement with “may be” is truth-functionally true. At least, harking back to the Monty Hall problem, so long as the person making the statement does not know whether it’s poisoned.


“Give me your lunch money, twerp!”


"hey, thats the quarter I swallowed 12 hrs ago. "


Meh… “you will not give me the penny”.


(gives penny)
Aha! But that means my statement was true, and therefore…
Oh, sorry. Did I forget to mention everything i say is a lie?
Butbutbut… nooooo!


That’ll just make you the recipient of a penny.


Oglaf (often NSFW)


For some reason my answer was “at the end of the game I will have more money than is left on the table” but that amounts to the same thing.


Wait. I get the answer. But there’s still no guarantee you’ll get the quarter. Just because you guessed right, the win is always “I will give you a coin, but it’ll be my choice.” Nothing that was said implies you could CHOOSE which coin you’d get by asking a clever question.

Right answer to the puzzle, but wrong conclusion drawn.

I know, I’m a bore, so damned pedantic. Carry on, clever puzzle solvers.


This topic was automatically closed after 5 days. New replies are no longer allowed.