To solve the exercise, first it is convenient to convert the mixed number to decimal:
[tex]34\frac{1}{2}=34+\frac{1}{2}=34+0.5=34.5[/tex]Now, you can use a rule of three:
[tex]\begin{gathered} 1\text{ hour}\rightarrow\text{\$13} \\ 34.5\text{ hours}\rightarrow\text{\$x} \end{gathered}[/tex][tex]\begin{gathered} x=\frac{34.5\text{ hours }\cdot\text{ \$13}}{1\text{ hour}} \\ x=\frac{34.5\cdot\text{ \$13}}{1} \\ x=34.5\cdot\text{ \$13} \\ x=\text{ \$}448.5 \end{gathered}[/tex]Therefore, Ethan did earn $ 448.50 last week.