Required: a. Firm A has a margin of 10%, sales of $510,000, and ROI of 19%. Calculate the firm's average total assets. b. Firm B has net income of $72,000, turnover of 1.30, and average total assets of $900,000. Calculate the firm's sales, margin, and ROI. c. Firm C has net income of $136,000, turnover of 1.91, and ROI of 23.70%. Calculate the firm's margin, sales, and average total assets