C.p = 70
Selling price = S.p = ?
% profit = 80
We will use the fomula
[tex]\text{profit percent =}\frac{s.p\text{ - c.p}}{c.p}\times100[/tex]substitute the values and solve for s.p
[tex]80=\frac{s.p-70}{70}\times100[/tex]Divide both-side of the equation by 100
[tex]0.8=\frac{s.p\text{ - 70}}{70}[/tex]Multiply both-side of the equation by 70
56 = s.p - 70
Add 70 to both-side of the equation
56 + 70 = s.p
126 = s.p
Therefore, the selling price is $126
