Does anyone remember or know the mathematical formula for determining the amount of oil that needs to be added to increase the percentage of lubrication in a gallon of methanol/oil/nitro mix ?

Fiddling around with my very rusty algebra, I came up with the following:

Ounces to be added = 128 * (%N - %O)/(1 - %N)

Where:
%N = desired oil % as a decimal
%O = original oil % as a decimal

eg: to increase the oil percentage of a gallon of fuel from 18% to 20% you would add 3.2 ounces of oil to the mix.

Ounces to be added = 128 * (0.2 - 0.18)/(1 - 0.2)

Does this sound correct ?

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