Thornton Computer Services, Inc. has been in business for six months. The following are basic operating data for that period: Month Service hours Revenue Operating costs July 120 $6,000 $4,300 Aug. 136 $6,800 $5,300 Sept. 260 $13,000 $ 7,100 Oct. 420 $21,000 $11,200 Nov. 320 $16,000 $ 9,100 Dec. 330 $16,500 $10,600 Required a. What is the average service revenue per hour in each month and the overall average for the six-month period? b. Use the high-low method to estimate the total monthly fixed cost and the variable cost per hour. c. Determine the average contribution margin per hour. Complete this question by entering your answers in the tabs below. Required A Required B Required C Use the high-low method to estimate the total monthly fixed cost and the variable cost per hour. Variable cost Fixed cost per hour per month