Dogs R Us reported a net profit margin of 10.5 percent, total asset...

Dogs R Us reported a net profit margin of 10.5 percent, total asset turnover of 0.75 times, debt-to-equity of 0.80 times, net income of $500,000, and dividends paid to common stockholders of $200,000. The firm has no preferred stock outstanding. Your final answers should be expressed as percentage numbers and keep two effective numbers after the decimal points. 

       1.a. What is Dogs R Us's return on assets?

       1.b. What is Dogs R Us's internal growth rate?

       1.c. What is Dogs R Us's return on equity ?

       1.d. What is Dogs R Us's sustainable growth rate?