Answer :
Total cost - (total cost * 30%) = discounted price
[tex]C - .3C = 18 \\ .7C =18 \\ C = \frac{18}{ \frac{7}{10}}\\ C=\frac{180}{7}\\ C= 25.7142857...[/tex]
[tex]C - .3C = 18 \\ .7C =18 \\ C = \frac{18}{ \frac{7}{10}}\\ C=\frac{180}{7}\\ C= 25.7142857...[/tex]