15. Knitting Needles produces several designs of sweaters for sale in specialty stores. The production rate for a style of sweater is 20 units per day (250 workdays per year). The sales rate for this sweater is 6 units per day. The setup cost for the knitting machine used to make the sweater is $62, and the cost to hold a sweater for a year is $12.

a. Determine the economic production lot.

b. What would the maximum inventory be if Knitting Needles wants to have 10 sweaters on hand (i.e., safety stock) when the first sweaters in a new production run begin to be completed?