If your total sales of the week are $125,000, then we have to calculate the 6% of this number to know the comision, so we can made a rule of 3:
[tex]\begin{gathered} 125000\to100 \\ x\to6 \end{gathered}[/tex]and the equation will be:
[tex]x=\frac{125000\cdot6}{100}=7500[/tex]So now the total pay will be the payment per hour plus the comission so:
[tex]\begin{gathered} T=20(10)+7500 \\ T=7700 \end{gathered}[/tex]