A furniture maker buys foam rubber x times per year. The delivery charge is a flat rate of $400 dollars per purchase regardless of how much is bought. The annual cost of storage is figured as $10,000/x, because the more frequent the purchase, the less it costs for storage. The annual cost is: C = 400x+10,000/x
A. Graph the function.
B. Find the number of purchases per year that minimizes the annual cost of delivery and storage.