please explain

Post Card Depot, an large retailer of post cards, orders 3,350,332 post cards per year from its manufacturer. Post Card Depot plans on ordering post card 18 times over the next year. Post Card Depot receives the same number of post cards each time it orders. The carrying cost is $0.11 per post card per year. The ordering cost is $427 per order. What is the annual carrying costs of post card inventory (round the answer to two decimal places)? Your