5. Apply the part period balancing (PPB) lot-sizing procedure to the following 12 periods of requirements data, indicating order receipts' size and period. Assume order costs are $100/order placed and inventory carrying cost is $1/unit/period. Calculate the inventory carrying costs on the basis of ending inventory values. Period 1 2 3 4 5 6 7 8 9 10 11 12 Requirements 70 30 35 60 60 25 35 70 45 70 80 55