19.A local dental practice decides to run a Groupon campaign. The campaign offered $345 worth of dental services (such as teeth whitening) for $150. For the total campaign, 250 coupons were sold. We estimate that 85% of the coupons will be redeemed, that 35% of the coupons will be redeemed by existing customers and that, on average, Groupon customers purchased 1.5 coupons. Let