Answer
Total salary over 10 years $S_{10}$ = 5 $\times$ 88500 = 442,500
Work Step by Step
Starting year's salary $a_{1}$= 33000
Raise in salary per year {common difference (d)} = 2500
Total salary over n years given by sum formula
$S_{n}$ = $\frac{n}{2}[ 2 a_{1} + (n - 1)d ]$
Total salary over 10 years $S_{10}$ = $\frac{10}{2}[ 2\times 33000 + (10 - 1)2500 ]$
= $5[ 66000 + 9 \times2500 ]$
= $5[ 66000 + 22500 ]$
= 5 $\times$\times 88500 = 442500
