4.3 ROE measures return to equity as net income divided by the book value of equity. ROC and ROA measure the return to all investors, including interest paid as well as net income to share- holders. ROC measures return versus long-term debt and equity. ROA measures return versus total assets. Average daily expenses are (15,762 + 11,357)/365 = $74.3 million. Accounts payable at the start of the year are $5,271 million. The average payment delay is therefore 5,271/74.3 = 71 days.