Hello,

I miss a bit of mathematic background to figure this out.
I was wandering when you are in a HU situation and there are three of a flush on the flop, how likely it is that my opponent has flopped a flush when I don't have a flushcard in my hand. And if I do have 1 flushcard in my hand, What will be the odds then for him to have floped a flush.
I know when I know my cards and the flopcards, there are 45 cards left in the deck which 9 of them are flush cards. So each card of him has 9/45th change to be a flushcard. But I know that is to simple. For instance, when his firstcard is a flushcard, he has 3 cards with a 8/44 change left to be a flushcard. And I know that that is also not the right calculation. It is more complicated then that to calculate it right.
I would be interesting to know how to calcualte this. And not only for a flush but for example also the change for an opponent to have floped a straight for instance.

Kind regards,

Tom