4-24. Compute and Interpret Coverage, Liquidity and Solvency Ratios Selected balance sheet and income statement information from Amazon for 2016 through 2018 follows. Required a. Compute profitability measures RNOA and ROE for 2018 and 2017. In which year are the measures stronger? b. Compute coverage metrics Times interest earned and Cash from operating activities to total debt for 2018 and 2017. Discuss any trends observed. c. Determine liquidity for the company for 2018 and 2017 by computing the current ratio and quick ratio. Is the company sufficiently liquid? Explain. What additional information about the accounting numbers that make up this ratio might be useful in helping us assess liquidity? Explain. d. Compute the Total liabilities-to-equity ratio and the Total debt to equity ratio for 2018 and 2017. Discuss any changes observed for each. e. What is the overall assessment of the company's credit risk from the analyses in parts a through d