Northgate Products Corp. sells gadgets and uses the perpetual inventory system. During the month of January 2016, the number of gadgets purchased and sold was as follows:

 

Assume the January 10 units were sold on account for $3 each, and the January 20 units were sold on account for $5 each.

*for specific identification, sold 50 units of opening inventory and 150 units of purchase #2

**for specific identification, sold 100 units of purchase #1 and 300 units from purchase #3

Required:

1. Complete the inventory record card, and calculate cost of goods sold and the cost of ending inventory under each of the following inventory cost flow assumptions:

a. FIFO

b. Specific identification

c. Weighted average.

2. Prepare the journal entries required to record purchases and sales using the FIFO inventory cost flow assumption.

3. Calculate the sum of cost of goods sold and ending inventory balances under each of the three assumptions. Explain the results.