Answer:
$13.50.
Step-by-step explanation:
80% = 0.80 as a decimal fraction.
The marked up price
= 7.50 + 0.80 * 7.50
= $13.50.
so the new price will just be 7.5 plus 80% of 7.5
[tex]\begin{array}{|c|ll} \cline{1-1} \textit{a\% of b}\\ \cline{1-1} \\ \left( \cfrac{a}{100} \right)\cdot b \\\\ \cline{1-1} \end{array}~\hspace{5em}\stackrel{\textit{80\% of 7.50}}{\left( \cfrac{80}{100} \right)7.50}\implies 6\hspace{5em}\underset{selling~price}{\stackrel{7.50~~ + ~~6}{13.50}}[/tex]