Journalize each of the following transactions assuming a perpetual inventory system.
Jan. 5 Sold merchandise to a customer for $6,800; terms 1 /10, n/30 (cost of sales $4,080).
7 Made a cash sale of $5,100 of merchandise to a customer today (cost of sales $3,060).
8 Sold merchandise for $12,400; terms 1 /10, n/30 (cost of sales $7,440). 15 Collected the amount owing from the credit customer of January 5.
Feb. 4, The customer of January 8 paid the balance owing.