Does anyone doubt that on average there will be 6 outs left?
If so, do you really beleive that on average there are 9 outs left in the 28 remaining cards??

So if you are only going to see 2 more cards, then how often will one of your suits fall? Well you will average 6 outs in 28 cards..so the chances that one of your suits will fall is 6:28 or about 4.5:1.