Calculating Average Operating Assets, Margin, Turnover, and Return on Investment East Mullett Manufacturing earned operating income last year as shown in the following income statement: Sales Cost of goods sold $531,250 280,000 Gross margin $251,250 Selling and administrative expense 180,900 Operating income $70,350 Less: Income taxes (@ 40%) 28,140 Net income $42,210 At the beginning of the year, the value of operating assets was $390,000. At the end of the year, the value of operating assets was $460,000. Required: For East Mullett Manufacturing, calculate the following: 1. Average operating assets 2. Margin (round to two decimal places) 3. Turnover (round to two decimal places) % 4. Return on investment (round to one decimal place) %