I am trying to calculate how my bet in to the quaddie pool would have affected the payout so i can test if what i am doing is profitable, here is what i have so far

say we had a Quaddie pool of $15085
and the payout on that race was $6788.40

that equate to about 2.22 for each $1 winning combination now we know people can bet the flexi so there is know way of knowing how many tickets won but that does not matter we only need to know the winning divi for $1

So if i put a $625 bet on and i had my unit for $1 do i add my amount to the pool less 20% then divide the pool by 3.22 to see what the dividend would have been with my selections added providing i got the winning combination

in the case above the pool would have been $15585 = 625 less 20% giving a winning divi of $4840