[BruceZ]

[ QUOTE ]
huh? you make you flush 9 times for every 36 tries

so if you are offering 9:1 and you chances of hitting are 25% so you should bluff an amount equivalent to 1/9th of 25% or 2.77% of the time you miss. so you should bet 27.77%
of 36 cards which is 9.9972 cards. 9 of which are flush cards and .9972 which are misses.

[/ QUOTE ]

You mean 2.777...% of the total time, not just of the time you miss. If you didn't round off, you would find that 27.777...% of 36 is exactly 10, not 9.9972. So you should bet on 9 flush cards plus exactly 1 other card. But of course you don't have to go through all of this. Your bet gives your opponent pot odds of 9-to-1, so you want the odds against your bluffing to be 9-to-1. Since 9 cards make your hand, you will bluff on exactly 1 card.