Hi Kris,
If you want you profit margin to be 18% then you are saying that you want your profit to be 18% of your sale price and hence your cost is 82% of your sale price. Let C be your cost and P your sale price then
C is 82% of P or
C = 82/100
P = 0.82 P
If you divide both sides by 0.82 you get
P = C/0.82
In the example you gave with C = $102,077.73 you get
P = $102,077.73/0.82 = $124,485.04
Penny
