To calculate the cost of goods sold (COGS) and the inventory balance using the weighted average method, we follow these steps:

1. Calculate Total Units and Cost of Inventory:

   • Beginning Inventory:
     • August 1: 10 units at $91 = $910
   • Purchases:
     • August 3: 15 units at $106 = $1,590
     • August 17: 20 units at $115 = $2,300
     • August 28: 10 units at $119 = $1,190

   Total Units Purchased:

   • 10 + 15 + 20 + 10 = 55 units

   Total Cost:

   • $910 + $1,590 + $2,300 + $1,190 = $6,990

2. Calculate Weighted Average Cost per Unit:

   $\text{Weighted Average Cost per Unit} = \frac{\text{Total Cost}}{\text{Total Units}} = \frac{6990}{55} \approx 127.09$

3. Calculate COGS for Sale of 23 Units on August 30:

   $\text{COGS} = \text{Units Sold} \times \text{Weighted Average Cost per Unit} = 23 \times 127.09 \approx 2,921.07$

4. Calculate Remaining Inventory:

   Units After Sale on August 30:

   • Total Units After Sales: 55 - 20 (sold on August 14) - 23 (sold on August 30) = 12 units remaining.

   Cost of Remaining Inventory:

   $\text{Remaining Inventory Cost} = 12 \times 127.09 \approx 1,525.08$

Final Results:

• COGS for the sale of 23 units on August 30: $2,921.07
• Inventory balance at August 30: $1,525.08

Would you like more details or have any questions? Here are some related questions to consider:

1. How would the COGS change if a different inventory valuation method were used?
2. What factors might affect the weighted average cost calculation?
3. How does a perpetual inventory system differ from a periodic system?
4. Can you explain how inventory purchases affect cash flow?
5. What impact do sales returns have on COGS and inventory balance?

Tip: Regularly update your inventory records to reflect real-time inventory levels and costs for more accurate financial reporting.