Mrs. Smith gets a base salary of $480 per month plus 8.8% commission of the value of the shoes that she sells.

(a) Last month, she sold 120 pairs of high heel’s shoes that cost $110 each and 210 pairs of sports shoes that cost $90 each. How much was her salary last month?

$

(b) This month, her salary is $3,122.64. She sells only high heel’s shoes. How many pairs of high heels shoes does she sell in this month?

pairs of high heels shoes

(a) Commission of a pair of high heel shoes: $110 × 8.8% = $9.68

Commission of a pair of sport shoes: $90 × 8.8% = $7.92

Total commission: $9.68 × 120 + $7.92 × 210 = $1,161.60 + $1,663.20 = $2,824.80

Total salary: $2,824.80 + $480 = $3,304.80

(b) Commission of a pair of high heel: $110 × 8.8% = $9.68

Total commission: $3,122.64 – $480 = $2,642.64

Sales of high heel’s shoes: $2,642.64 ÷ $9.68 = 273