a company began january with 4,000 units of its principal product. the cost of each unit is $8. inventory transactions for the month of january are as follows: date of purchase purchases units unit cost* total cost january 10 3,000 $ 9 $ 27,000 january 18 4,000 10 40,000 totals 7,000 $ 67,000 * includes purchase price and cost of freight. sales date of sale units january 5 2,000 january 12 1,000 january 20 3,000 total 6,000 5,000 units were on hand at the end of the month.