Is it possible to reverse calculate a gross sum minus 35% commission x 20% tax only by knowing the final (net) payment. E.g 550-231(192.5+38.5)=319 i.e when only 319 is known? Is there a (simple) formula for maths dummies I could use on a calculator?
Reverse calculation
- Thread starter dohdoh
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mmm4444bot
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Divide the final (net) payment by 0.58
Thank you so much!
HallsofIvy
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mmm4444bot's point is that if the initial cost is A then commission c (as a decimal) is cA and the tax t of that is ctA so that you have A- (cA+ ctA)= A(1- c- ct). To go from A- (cA+ ctA)= A(1- c- ct)= P to A, divide both sides by 1- c- ct: A= P/(1- c- ct).
In your first example, A was 550, c was .35, and t was .2 so that 1- c- ct= 1- .35- (.35)(.2)= 1- .35- .07= 1- .42= .58. Thus "Divide the final (net) payment by 0.58".
Now, you want to set t= .175 so that ct= .35(.175)= 0.06125 and 1- c- ct= 1- .35- .06125= 1- 0.41125= 0.58875. Divide by 0.58875.
In your first example, A was 550, c was .35, and t was .2 so that 1- c- ct= 1- .35- (.35)(.2)= 1- .35- .07= 1- .42= .58. Thus "Divide the final (net) payment by 0.58".
Now, you want to set t= .175 so that ct= .35(.175)= 0.06125 and 1- c- ct= 1- .35- .06125= 1- 0.41125= 0.58875. Divide by 0.58875.