I Will Be Hanged

Here is an old goodie.

Puzzle. A criminal is sentenced to death. He is offered the last word. He is allowed to make one statement. If the statement is true, the criminal will be electrocuted. If the statement is false, he will be hanged. Can you find a good piece of advice for this man?

The standard answer to this puzzle is for the criminal to say, “I will be hanged.” This creates a paradox. If he is hanged, the statement is true, and he should be electrocuted. If he is electrocuted, the statement is false, and he should be hanged.

Thinking about it, any paradox works. If the man says, “This statement is false,” then the type of punishment he gets can’t be determined.

Thinking about it some more, asking a question instead of making a statement will confuse his executioners all the same.

One of my students advised the criminal to stay silent. This was not my favorite solution, as staying silent requires some concentration. My favorite solution was the statement, “It will rain exactly a thousand years from now.” This way, the criminal can relax, at least for a thousand years.



  1. Lazar Ilic:

    Yikes at the ominous title Dr. Tanya Khovanova. One would hope this is not an actual factual prediction but merely a puzzle post… or perhaps stemmed from a game of Mafia or Werewolf with some kiddos.

  2. Zarunias:

    I wouldn’t want to create a paradox in this situation. Who knows how the executioners react in such a case. I am also not sure about the rain prediction. Computers are getting better at wheather forecasting.
    So I would say: “I will either get hanged or you give me 1000000 Dollars, let me go for now and wait 1000 years with the execution of my death penalty.”
    This way not only the executioners are able to fulfill their words but I also get some additional benefits.

    Also in such cases I strongly advise in hiring a lawyer. You want to be sure about all the conditions and you want to use bulletproof wordings (you know, they might get the idea to simultaneosly hang and electrocute me, after all they said “if”, and not “if and only if”).

  3. lvps1000vm:

    P = NP

    The prisoner will die anyway, but at least his sacrifice will lead the world to a discovery. We can erect a statue in his memory and give his heirs the reward from the Millenium Prize.

    That assumes that the captors have a flawless method to resolve the statement, and that the world can watch the execution or at least exhume the corpse to determine cause of death.

    (You may change it to any unsolved mathematical or logical truth of your liking, as long as is binary).

  4. tanyakh:

    Nice idea, lvps. Thinking about helping humanity even before death.

  5. Dennis Lawson:

    ‘God exists’. True or false?

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