Langley Inc. inventory records for a particular development program show the following at October 31, 2017:

At October 31, 10 of these programs are on hand. Langley uses the perpetual inventory system.

Requirements

1. Journalize for Langley:

a. Total October purchases in one summary entry. All purchases were on credit.

b. Total October sales and cost of goods sold in two summary entries. The selling price was $500 per unit, and all sales were on credit. Langley uses the FIFO inventory method.

2. Under FIFO, how much gross profit would Langley earn on these transactions? What is the FIFO cost of Langley's ending inventory?