Carlos,


I always find it difficult to explain probability, but I will give it a try.


C(m,n) is the number of ways that you can pick n items from a list of length m if the order that you pick them is unimportant.


To figure out the probability of flopping a flush draw, you need to calculate the number of possible flops and the number of flops with flush draws. Then


(prob flushdraw) = (number flushdraws) / (number flops)


The number of possible flops is C(52-2, 3) if you hold 2 cards.


If you hold two suited cards, there are C(13-2,2) ways to choose 2 cards in your suit from the remaining 11 cards. There will also be one other, non-suited card in the flop. There are 13*3 possible non-suited cards.


(number flushdraw) = C(11,2)* 13*3


(number flops) = C(50,3)


(prob flushdraw) = C(11,3) * 13*3/ C(50,3) = 0.328316


I will attach a url with some basic poker probability.


Lastly, it is very easy to make mistakes in reasoning when doing probability, so it is best to check answers before posting them. I will foolishly skip the verification step in this post do to lack of time. Hopefully, at least the reasoning is readable even if there is an error.