probability

[serell]

bluff magazine stated that their is 55%chance the flop will contain two suited cards, is this correct and can you show me the math. I thought it would be 44%. thanks

[drbst]

The probability that three randomly chosen cards from a deck of 52 cards are all of different suits is 39/51 * 26/50. The probability that all are of one suit is 12/51 * 11/50. Therefore the probability that exactly two cards are of the same suit is the probability that they are not all diffent minus the probability that all are of the same suit, which gives: 1 - 39/51 * 26/50 - 12/51 * 11/50 = 55%

[neghe]

the probability for cards in three different suits is:
39/51 * 26/50 about 40%. So the odds for at least two suited cards is ~60%. Three cards in one suit is 12/52*11/51
about 5%, so two cards exactly is ~55% if my maths are right.