In response to complaints about high prices, a grocery chain runs the following advertising campaign: "If you pay your child $1.50 to go buy $50 worth of groceries, then your child makes twice as much on the trip as we do." You've collected the following information from the grocery chain's financial statements: ($ in millions) Sales $680.0 Net Income 10.2 Total assets 380.0 Total debt 270.0 a. What is the profit margin for child and store? (Do not round intermediate calculations and enter your answers as a percent rounded to 2 decimal places, e.g., 32.16.) b. What is the store's ROE? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) a Child's profit margin Store's profit margin b. Store's ROE % %