How is beginning inventory calculated in a periodic inventory system using the weighted average cost flow method?

The calculation of beginning inventory in a periodic inventory system using the weighted average cost flow method involves understanding the relationship between the total goods available for sale, net purchases, and inventory levels.

The correct approach starts by recognizing that total goods available for sale consists of the beginning inventory plus any net purchases made during the accounting period. By rearranging this relationship, beginning inventory can be determined by subtracting net purchases from total goods available for sale. This demonstrates how the total remaining inventory at the start of the period is affected by the stock added through purchases.

Thus, beginning inventory is effectively calculated by determining how much of the total goods available to sell at the end of the period can be attributed to what already existed before any new purchases were made. The weighted average cost flow method then takes this computed beginning inventory, along with purchases, to establish an average cost for valuation purposes.

The other options do not provide a relevant method to derive beginning inventory. Adding net purchases or considering average cost of goods sold and fixed costs do not align with the necessary calculations to determine starting inventory in this system.