Exercise 11-9 Mixed cost at different levels of activity LO 11-1 Walton Corporation paid one of its sales representatives $4,000 during the month of March. The rep is paid a base salary plus $14 per unit of product sold. During March, the rep sold 120 units. Required Calculate the total monthly cost of the sales representative's salary for each of the following months: April 160 May 7 0 June 170 July 8 0 Month Number of units sold Total variable cost I Total fixed cost Total salary cost $ 0 % 0 % 0 %