Proton Company has 6 sales representatives and pays them a salary of $20,000 each per month. It also pays 10 percent commission on the sale price of each refrigerator. Each refrigerator is sold at a price of $10,000. Compute the total selling expenses (associated with the sales representatives) incurred by Proton for the month of August. Assume each of the representatives sold 5 refrigerators in the month of August