The answer's 50%, but I'm not sure how they arrived at that number if someone can show the steps were taken to solve it. Thank you!

ILUL - POIL 40) Marshall Networks, Inc. has a total asset turnover of 2.5 and a net profit margin of 3.5%. The firm has a return on equity of 17.5%. (See formula sheet equation 2 for definitions of these ratios.) Calculate Marshall's debt ratio (debt / total assets). (Round to the nearest percent.)