A company manufactures hair dryers. It buys some of the components, but it makes the heating element, which it can produce at the rate of 840 per day....

A company manufactures hair dryers. It buys some of the components, but it makes the heating element, which it can produce at the rate of 840 per day. Hair dryers are assembled daily, 249 days a year, at a rate of 320 per day. Because of the disparity between the production and usage rates, the heating elements are periodically produced in batches of 2,400 units.