A retailer buys a dishwasher for $500.00 less 25%, 10%. The store prices the merchandise at a regular selling price to cover expenses of 15% of the regular selling price and a net profit of 20% of the regular selling price. During a clearance sale, the appliance is sold at a markdown of 20%. a) What is the regular selling price? b) What rate of markup based on cost was realized at the regular selling price? c) What is the clearance sale price? d) What is the operating profit or loss during the sale?