C.p = 70
Selling price = S.p = ?
% profit = 80
We will use the fomula
![\text{profit percent =}\frac{s.p\text{ - c.p}}{c.p}*100](https://img.qammunity.org/2023/formulas/mathematics/college/l60t5vl609npl2vmfbfm55pzw0w05f4ex6.png)
substitute the values and solve for s.p
![80=(s.p-70)/(70)*100](https://img.qammunity.org/2023/formulas/mathematics/college/jxr29z2ydf6a5u0f7b1u2tptj2nbjj9xr6.png)
Divide both-side of the equation by 100
![0.8=\frac{s.p\text{ - 70}}{70}](https://img.qammunity.org/2023/formulas/mathematics/college/3hneuzfpn3lpvuxlw2fr2tsvsih699nh19.png)
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