b$)$ Caravan Engineering uses the following formula to determine how many temperature probe casings to order: Qo $=$ square root of $(2$DS$/$H$)$ or Q$\_$O$=(2$DS$/$H$)$

where Qo is the order quantity, D is the annual demand, S is the ordering cost, and H is the annual holding cost per unit. The firm$$s annual demand is four hundred units, the ordering cost is thirty six dollars, and the annual holding cost is two dollars per unit. The firm$$s inventory manager wants to calculate the order quantity.