You take the 7th square root of your 10% bonus to calculate how much % each individual odd in your accumulator is worth extra.

So in this case you have 7 bets in your accumulator, for a 10% bonus so you would take the 7th square root of "1.1" (1 being your normal odd and you add 10% bonus) so that would be 1.013709. This means each individual odd in your parlay is worth 1.3709% extra.

So if your parlay was 2x2x2x2x2x2x2 in this case your individual odds worth would be 2.027 (2x1.013709).

http://www.calculatorsoup.com/calculators/algebra/radical.phpAfter that you can use your accumulator like you would treat any accumulator arb.