Solution
Step 1
Write an expression for the sales tax she paid and the percentage off
[tex]\begin{gathered} \text{Percentage off =30\%. Therefore, the actual \% left = 100 -30 = 70\%} \\ \frac{100}{70}=\frac{\cos t\text{ of both video games}}{x} \\ \text{where x = cost of video games after the \% off} \\ \end{gathered}[/tex][tex]\begin{gathered} \text{For the sales tax} \\ \frac{100}{8.25}=\frac{\cos t\text{ of two shirts}}{y} \\ \text{where y = amount of sales tax paid} \end{gathered}[/tex]Step 2
Find her total bill after substitution
[tex]\begin{gathered} \text{Amount paid after 30\% off will be} \\ \frac{100}{70}=\frac{60}{x} \\ 4200\text{ = 100x} \\ x=\text{ }\frac{4200}{100} \\ x=42\text{ dollars} \end{gathered}[/tex][tex]\begin{gathered} \text{Amount of sales tax} \\ \frac{100}{8.25}=\frac{60}{y} \\ 495\text{ = 100y} \\ y\text{ =\$4.95} \end{gathered}[/tex]Her total bill thereore = 42 +4.95 =$46.95
