We have a normal deck of 52 cards. We want to do the following magic trick:

A person from the audience chooses 5 random cards. The magician's assistant looks at the 5 cards, chooses 4 of them, hands them to the magician one by one face up and keeps the other one hidden. The magician then guesses the fifth card (the one that the assistant kept hidden) just by looking at the 4 cards he was handed in.

Is it possible to devise a strategy, so that no matter what the original 5 cards were, the trick always works?

(In reply to Hows dis? by Hank)

Now that i think about it, since it's supposed to be a "magic" trick, the assistant is probably not able to carefully lay out the cards - that would be too obvious.

It's probably OK to do something as non-obvious as passing the four cards (in one mini-deck) either all face up or face down - the audience will probably not see any meaning in that, but if the assistant lays out the four cards all in different manner it may be suspicious.

Posted by levik on 2003-05-08 09:17:59