We have that for seven and a half hours, you get 72$, then we have the following rule of three:
[tex]\begin{gathered} 72\rightarrow7\frac{1}{2}hours \\ x\rightarrow1hour \end{gathered}[/tex]then we have that:
[tex]\begin{gathered} x=\frac{72\cdot1}{7\frac{1}{2}}=\frac{72}{\frac{15}{2}}=\frac{144}{15}=9.6 \\ x=9.6 \end{gathered}[/tex]therefore, for each hour, you get $9.6
So, for 40 hours we have:
[tex]40\cdot9.6=384[/tex]finally, we have that for 40 hours you get $384
