Clarks Incorporated, a shoe retailer, sells boots in different styles. In early November the company starts selling $$SunBoots$$ to customers for $$60$ per pair. When a customer purchases a pair of SunBoots, Clarks also gives the customer a $20\%$ discount coupon for any additional future purchases made in the next $30$ days. Customers can$$t obtain the discount coupon otherwise. Clarks anticipates that approximately $10\%$ of customers will utilize the coupon, and that on average those customers will purchase additional goods that normally sell for $$350.$