Sheridan Medical manufactures hospital beds and other institutional furniture. The company's comparative balance sheet and income statement for 2019 and 2020 follow. Liabilities and Stockholders' Equity Sheridan Medical Comparative Income Statement and Statement of Retained Earnings For the Year Calculate the following profitability ratios for 2020. (Round answers to 1 decimal place, e.g. 50.1\%.) Calculate the following profitability ratios for 2020 . (Round answers to 1 decimal place, e.g. 50.1\%.) % a. Gross margin percentage % b. Return on assets c. Return on common stockholders' equity %