Determining missing items in return on investment computation One item is omitted from each of the following computations of the return on investment: Return on Investment Profit Margin X Investment Turnover 18 % 10 % (a) (b) 16 % 0.75 30 % X 1.5 (c) 20 % 12 % (d) 15 % 1.2 Determine the missing items identified by the letters as shown above. If required, round your answers to two decimal places. (a) % (b) (c) (d) % (e) %