Thapter 7: Astro Corporation uses the perpetual inventory system. Information related to Astro's inventory at October 31 is given below: Required: -5how calculations and determine the ending inventory using the FiFO cost formula at October 31 ( 5 Marks) ow calculations and determine the ending inventory using the weighted average cost formula at October 31 . (5 Marks) itermine sales, cost of sales and gross profit under both inventory methods (FIFO and average cost). (10 Marks)