A company will begin stocking remote control devices. Expected annually demand is $800$ units. The controllers can be purchased from either supplier A or supplier B$.$ Their price lists are as follows: Ordering cost is $40$ and annual holding cost is estimated at $25$ percent of unit price per unit. Whic supplier should be used and what order quantity is optimal if the intent is to minimize total cost. The answer is A and $500,$ but i cant seem to get to that solution