It would be great if u can explain

The following information applies to the questions displayed below. At the beginning of July, CD City has a balance in inventory of $3,400. The following transactions occur during the month of July. July 3 Purchase CDs on account from wholesale Music for $2.300, terms 1/10, n/30. July 4 Pay cash for freight charges related to the July 3 purchase from Wholesale Music, $110 July 9 Return incorrectly ordered CDs to Wholesale Music and receive credit, $200 July 11 Pay Wholesale Music in full. July 12 Sell CDs to customers on account, $5,800, that had a cost of $3,000. July 15 Receive full payment from customers related to the sale on July 12. July 18 Purchase CDs on account from Music Supply for $3,100, terms 1/10, n/30. July 22 Sell CDs to customers for cash, $4,200, that had a cost of $2,500 July 28 Return CDs to Music Supply and receive credit of $300 July 30 Pay Music Supply in full