"green thumb, a manufacturer of lawn care equipment, has introduced a new product. the anticipated demand is normally distributed with a mean of = 100 and a standard deviation of = 40. each unit costs $150 to manufacture and the introductory price is to be $200 to achieve this level of sales. any unsold units at the end of the season are unlikely to be very valuable and will be disposed off in a fire sale for $50 each. it costs $20 to hold a unit in inventory for the entire season. how many units should green thumb manufacture for sale