At the beginning of the year, Seller Company had 700 units with a cost of $3 per unit in its beginning inventory. The following inventory transactions occurred during the month of January: Jan 3: Sold 550 units on account for $6 each Jan 9: Purchased 1000 units on account for $4 per unit Jan 15: Sold 850 units for cash for $7 each Prepare journal entries to record the January transactions assuming that Seller Company uses a periodic inventory system under (a) FIFO and (b) Average