[Henke]

An infinitely difficult way would be to do it experimentally by the definition of probability.

1. Shuffle a deck of cards with a perfect shuffle (meaning a shuffle that makes each of the 52! possible permutations equally probable).
2. Remove four cards of one suit, and one card of another suit.
3. Reshuffle the deck perfectly (it's now 46! permutations that need to be equally probable).
4. Deal two cards.

Repeat steps 3 and 4 n times, and let m be the number of times that the cards in step 3 contain at least one card of the same suit as the four previously removed. Now you just have to let n approach infinity and divide m by n.

Hard enough? [img]/images/graemlins/grin.gif[/img]