[lorinda]

I would simplify by working out how much each player returns on average.

For instance a -10% ROI player in a $11 returns $9.90

Add all the values together for the total prize pool and then work out what % of the new prize pool each player wins.

so if all the players are -10% ROI, the total is $99 so they all have $9.90 from $99 in the prize pool, which returns them $9.90 = 0% ROI
You then subtract 9.09% for rake, and they are all -9.09%

Lori