In response to complaints about high prices, a grocery chain runs the following advertising campaign. "If you pay your child $1 to go buy $31 worth of groceries. then your child makes about twice as much on the trip as we do.- You've collected the following information from the grocery chain's financial statements: a. What is the child's profit margin? (Do not round intermediate calculations and enter your answer os a percent rounded to 2 decimal places, e.9., 32.16.) b. What is the store's profit margin? (Do not round intermediote calculations and enter your answer as a percent rounded to 2 decimal places, e.g., 32.16.) c. What is the store's ROE? (Do not round intermediate calculations and enter your answer as a percent rounded to 2 decimal places, e.9. 3216.)