a. Firm D has net income of $33,500, sales of $880,000, and average total assets of $575,000. Calculate the firm's margin, turnover, and ROI. Margin: Turnover: ROI: b. Firm E has net income of $67,000, sales of $1,300,000, and ROI of 12%. Calculate the firm's turnover and average total assets. Turnover Average Total Assets: c. Firm F has ROI of 12.6%, average total assets of $1,765,900, and turnover of 1.5. Calculate the firm's sales, margin, and net income. Net Income: Sales: Margin