The mean inside diameter of a sample of 200 washers manufactured by a machine is 0.502 in. and the standard deviation is 0.005 in. The application for the washers permits a tolerance in the diameter of 0.496 in. in to 0.508 in. If the diameter is outside this tolerance, the washers are deemed defective and are sold as scrap. Assuming a normal distribution of washer diameters:
a) What percentage of washers are discarded?
b) If 20,000 washers are manufactured daily, how many are discarded daily?
c) 25 washers have a combined mass of 1 lb. how much money is recovered per day from the sale of scrap washers?