ST15.2 Optimal Mark-Up on Price. TLC Lawncare, Inc., provides fertilizer and weed control lawn services to residential customers. Its seasonal service package, regularly priced at

$250, includes several chemical spray treatments. As part of an effort to expand its customer base, TLC offered $50 off its regular price to customers in the Dallas area. Response was enthusiastic, with sales rising to 5750 units (packages) from the 3250 units sold in the same period last year?