The other way people do it is say 6 out of 47 cards help, so you'll catch your card 13% of the time. So the ratio is 13%:87%. Divide both sides by 13% and we get 1:6.7 (note it's off by .1 because of rounding errors).

I understand the ratios now, thanks. But, you confused me with the 6 out of 47 cards left. Is that right after the flop? And the turns about to hit? I have been using the 4, 2 rule. So wouldn't I multiply the 6 by 4?

Or have I been doing it wrong the whole time?

And for my other post, yeah the pot is 120 and my opponent bet 20 into it.