rving Music Shop gives its customers coupons redeemable for a poster plus a Dixie Chicks CD. One coupon is issued for each dollar of sales. On the surrender of 100 coupons and $5.00 cash, the poster and CD are given to the customer. It is estimated that 80% of the coupons will be presented for redemption. Sales for the first period were $700,000, and the coupons redeemed totaled 340,000. Sales for the second period were $840,000, and the coupons redeemed totaled 850,000. Irving Music Shop bought 20,000 posters at $2.00/poster and 20,000 CDs at $6.00/CD.