Involve the just-in-time inventory discussed in the chapter introduction.
The Economic Order Quantity (EOQ) model uses the assumptions in exercise 61 to determine the optimal quantity $Q$ to order at any given time. Assume that $D$ items are ordered annually, so that the number of shipments equals $\frac{n}{Q}$. If $C_{o}$ is the cost of placing an order and $C_{c}$ is the annual cost for storing an item in inventory, then the total annual cost is given by $f(Q)=C_{c} \frac{D}{Q}+C_{c} \frac{Q}{2} .$ Find the value of $Q$ that minimizes the total cost. For the optimal order size, show that the total ordering cost $C_{o} \frac{D}{Q}$ equals the total carrying cost (for storage) $C_{c} \frac{Q}{2}$.