Estimated demand for gold-filled lockets at sam's bargain jewelry and housewares is 2,420 lockets a year. manager veronica winters has indicated that the ordering cost is $45, the annual carrying cost is $.18 per locket and that the following price schedule applies: 1 to 599 lockets, $.90 each; 600 to 1,199 lockets, $.80 each; and 1,200 or more, $.75 each. what order size will minimize total cost?