If [B]Final[/B] must = 200, is it possible to reverse evaluate for the values of A1, A2, X1, X2? X1 = bytes of data X2 = bytes of data A1 = percentage A2 = percentage Formulas to get the two percentages: A1 = 1 - e^(-X1/376000000000) A2 = 1 - e^(-X2/752000000000) Formula to get the final number: [B]Final[/B] = (A1 + (A1 * A2))