Vernon Computer Services, Inc has been in business for six months. The following are basic operating data for that period: July Service hours Revenue Operating costs 118 $6,372 $4,270 Aug 132 $7,128 $5,210 Month Sept. Oct. Nov. Dec. 264 424 322 33e $14,256 $22,896 $17,388 $17,820 $ 7,140 $11,140 $ 9,162 $10,570 Required a. What is the average service revenue per hour in each month and the overall average for the six-month perod? 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