Answer:
After each purchase
Step-by-step explanation:
perpetual inventory system can be regarded as a kind of inventory management that utilize technology in the documentation of real-time transactions whenever stock is received or sold, this method is reliable and the efficiency is high compare to
periodic inventory system. It should be noted that When using a perpetual inventory system and the weighted-average inventory costing method, a new weighted-average cost per unit is computed after each purchase. perpetual inventory system can be use by gocesory stores.