Explanation
Step 1
set the equation
let s represent the total sales
let T represents the monthly salary
so,
monthly salary= base salary + commisions
replace
T=3000+(2 % of the sales)
[tex]\begin{gathered} T=3000+\frac{2}{100}s \\ T=3000+0.02s \end{gathered}[/tex]Step 2
now, to know how much money the salary will be,
Let
sales= s= 90000
[tex]\begin{gathered} T=3000+0.02s \\ T=3000+0.02(90000) \\ T=3000+1800 \\ T=4800 \\ 4800 \end{gathered}[/tex]I hope this helps you