Consider a retail firm with a net profit margin of 3.42 %​, a total asset turnover of 1.88​, total assets of $ 45.9 ​million, and a book value of equity of $ 18.6 million. a. What is the​ firm's current​ ROE? b. If the firm increased its net profit margin to 4.19 %​, what would be its​ ROE?