Daraz Mall Company provides free examination of its products for 7 days. If not completely satisfied, a customer can return the product within that period and get a full refund. According to past records of the company, an average of 2 of every 10 products sold by this company are returned for a refund. a. Find the probability that exactly 6 of the 40 products sold by this company on a given day will be returned for a refund. b. Find the probability that no more than 3 of the 20 products sold by this company on a given day will be returned for a refund