Jimbob Co. is a merchandising company that buys and resells tires for rally race cars. The company's income statements for the last two years are given below: Last year This year Units sold 2,200 2,000 Sales $330,000 $300,000 Less cost of goods sold 220,000 200,000 Gross margin 110,000 100,000 Less operating expenses 65,000 60,000 Net income $45,000 $40,000 The company has no beginning or ending inventories. Required: a. Estimate the company's total variable cost per unit for operating expenses. b. What is the company's total of fixed costs per year? c. Compute the company's contribution margin for this year.