[Al_Capone_Junior]

Forget all the exact math, it's fairly straightforward in deciding what to do here, and why.

First off, will your two pair be good if it hits? Given that it will put a three-str8 on the board, you can't be all that sure about this. If the board was 4 6 5 K you would have a better feeling about 6's and 5s than you would about queens and jacks on a board of K Q J 8. Still, in either case two pair is certainly far less than a lock. This must be factored in when deciding whether to call a bet.

In most cases, your trips cards will be good, so they are usually worth a solid two outs.

Each of your backdoor draws are worth approximately the same as ONE extra out, assuming there is a high % chance of your backdoor hand holding up if it hits. Obviously a backdoor to the butt-end of a str8 is pretty much worthless. In your example, you'll only have a one card str8, so it won't be the nuts, keep that in mind.

You should keep in mind at all times that effective odds are most important in making all decisions. Also, position relative to a bettor is highly important, as you might just get raised behind if you call an EP bet.

al