ou operate a computer store where demand for a particular laptop is $12,000$ per

year. Due to the price of security, your annual inventory costs are $50\%$ of what you paid for

a laptop. The supplier of the laptop charges an order cost of $$80,000$ independent of the size

of the order. You must order an integer number of phones. In addition, the supplier applies

an all$-$units discount scheme depending on the size of your order. This scheme is