Pot Odds Question

[nepenthe]

Hi, new user here. I've been browsing these forums for the past few days and found the information contained within them invaluable. I have a question about computing the pot odds for an open-ended straight / 4 to a flush at the flop. By my calculations, the chances of obtaining a completed straight by the time you reach river is 31.45%, while chances of completing the flush by river is 34.97%. I also calculate the chances of completing either by the river to be 54.12% (Please correct me if I'm wrong here). My question is, how do you compute the chances that you'll either complete the straight, or get one more flush card (but NOT two) to complete the flush? Say you have 8 /images/graemlins/heart.gif9 /images/graemlins/heart.gif and the flop comes:
T /images/graemlins/club.gif7 /images/graemlins/heart.gif2 /images/graemlins/heart.gif
I either want 6 or J of any suit for a straight, or want one more heart for a flush but not two, as I fear an A /images/graemlins/heart.gif or similar to be lurking somewhere.

Any help appreciated.

[pokeryogi]

If there is an Ace out there drawing runner runner, more power to you. You want this. It makes more money for you in the long run. But if you really want to know the odds for runner runner hearts, divide the total possible turn & river cards (47 x 46) by the total number of possible runner runner flushes (9x8) - this number would actually be 8x7 with the assumption your opponent had the Ace flush card.
I could be wrong on my math, but I think its close.

[LetsRock]

You have 15 outs. It's roughly 2:1 to catch one of your outs each time. Your odds are naturally a little better with 2 to come, but with so many outs you really don't need to be so precise that you start doing algebra or calculus (or whatever complicated mathematicl gyration is used to figure probability) during the game. Try to keep it as simple as possible.

Is the pot ever going to be small enough that you can't get 2:1 to draw to 15 outs? Would 1.65:1 really make a difference? (I think not.)

Don't worry about the 4 flush until it happens.