if we take 85 to be the 100%, how much is the retail price, namely the 170%?
[tex]\bf \begin{array}{ccll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
85&100\\
x&170
\end{array}\implies \cfrac{85}{x}=\cfrac{100}{170}\implies \cfrac{85\cdot 170}{100}=x[/tex]
so the retail price is "x", thus the profit will be x - 85.
