Muffler Incorporated produces floor mats for cars and trucks. The owner, Kenneth Muffler, asked you to assist him in estimating his maintenance costs. Together, Mr. Muffler and you determined that the single best cost driver for maintenance costs was machine hours Below are data from the previous fiscal year for maintenance expense and machine hours: Month Maintenance Expense Machine Hours 1 $ 3,120 2,200 3,310 2,300 3 A 3,490 2,400 3,620 2,430 3,620 2,280 3,680 2,440 3,610 2,420 3,420 2,390 9 3,140 2,210 10 2,880. 2,080 11 2,780 1,690 12 2,940 2,070 Using the high-low method, unit variable cost is calculated to be