Tarry for the Nonce

September 16, 2003

Mensa Material?

Filed under: Brain Teasers — lmwalker @ 10:41 am

I found the source of MSN quizzes.

January 14, 2003


Filed under: Brain Teasers — lmwalker @ 3:10 pm

Here is the problem from the twisted mind of Anatoly Delm:

There are 100 mathematicians locked in a prison, each in solitary confinement. The warden, having a good day, assembles them in a large room and gives them the following scenario: every day he will remove a single, randomly chosen prisoner from their cell and then randomly decide whether to allow that prisoner to visit the library. The prisoner is then returned to their cell and the process is repeated the following day. Within the library, the prisoner has a single method of communication with the next visitor to the library: the choice of turning the light on or off. Whenever a prisoner visits the library, he also has the choice of declaring that all 100 prisoners have visited the library at least once or of decling to answer. If he declines to answer, no harm is done. If he is correct, all prisoners go free. If he is wrong, the exercise is concluded and they must each die in solitary confinement, with nary a slide rule for comfort. They have one hour to commiserate and devise a system. Bearing in mind that the warden may randomly select the same prisoner repeatedly, how should the mathematicians gain their freedom?

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