Answer and Explanation:
The fixed quantity inventory system, the quantity of an order or the lot size is fixed in nature i.e. the similar amount means the quantity is ordered each and every time. It could be managed by continonusly watching the level of inventory. Example - economic order quantity
On the other hand, the fixed period inventory system is a system in which the inventory is to be checked at fixed inventory. It is same as the periodic reveiw system instead of the continuous basis. Example - drugstore