4. The manager at San Marcos Oil Lubes needs to forecast future shop overhead costs, which include variable and fixed costs. They believe the total overhead varies with the # of oil changes. Below is a listing of data for the several months earlier in the year. Oil changes Total Costs January 2900 $25,400 February 2800 $25,200 March 3300 $26,000 April 3600 $30,000 May 4300 $29,000 June 1800 $18,500 July 3700 $26,800 Using the high-low method, what would San Marcos Oil Lubes predict the total costs to be when they perform 3900 oil changes? a. $26,285 b. $10,940 C. $28,460 d. $27,320 5. When working with the cost equation which of the below is a true statement. a. Slope = F.C. b. Slope = Total Variable Costs C. Y Intercept = Fixed Costs d. TC = Y Intercept + Slope