Artemis is paid a weekly commission of 4% on net sales of $6000, 8% on the next $3000, and 12.5% on all further sales. Her gross sales for a week were $11 160, and sales returns and allowances were $120.
(a) What were her gross earnings for the week?
(b) What was her average hourly rate of pay for the week if she worked 43 hours?