A humanitarian aid service operates a laboratory that maintains an inventory of test kits for a variety of procedures. It uses 780 kits each year. Ordering costs are $15 and holding costs are $3 per kit per year. The new price list indicates that orders of fewer than 73 kits will cost $60 per kit, 73 through 144 kits will cost $56, and orders of more than 144 kits will cost $53 per kit. Determine the optimal order quantity and total cost.