Please show all workings in an understandable format

Question 1 (A) In response to customer complaints about rising prices of food items, a supermarket responds by making the following offer: For every $10 of purchase, the customers will earn $1 worth of coupons and this way they will end up making twice as much as the supermarket. If the supermarket makes $500 worth of total sales to all customers taken together, how much will it need to restrict its costs to so as to honour the offer? Question 1 (B) Use the following information to answer the question that follow: Net Income Profit margin A/R Credit sales : $205,000 : 7.80% : $151,642 : 60% of total sales Compute the days' sales in receivables