Answer:
Mercury company
Net Income $180,000
Interest expense 10,000
Earnings before tax = $170,000
Total assets at the beginning of the year 810,000
Total assets at the end of the year 740,000
Total common stockholders' equity at the beginning of the year 520,000
Total common stockholders' equity at the end of the year 510,000
Return on equity = Net income divided by Shareholders equity
= $170,000 / $510,000
= 33.33%