Franklin Corporation paid one of its sales representatives $8,000 during the month of March. The rep is paid a base salary plus $12 per unit of product sold. During March, the rep sold 180 units. Required Calculate the total monthly cost of the sales representative's salary for each of the following months: Month Number of units Total variable cost April May June July 220 130 230 140 Total fixed cost Total salary cost $ 0 $ 0 0 $ 0