David and Beth Sheba Run a Health Food Store

Essay

David and Beth Sheba run a health food store.Their top selling item is called Heavenly Kelp.The annual demand for this is 810 units, and demand is constant throughout the year.The cost of placing an order is $20, while the holding cost per unit per year is $4.
(a)How many orders per year should be placed if they wish to minimize their total cost?
(b)What is the minimum possible annual holding and ordering cost?