I need help, why i have the july 30 bad? if you can explain ill appreciated it! thank you.

Prepare journal entries to record the following merchandising transactions of Cabela's, which uses the perpetual inventory system and the gross method. (Hint: It will help to identify each receivable and payable, for example, record the purchase on July 1 in Accounts Payable-Boden.) Jul. 1 Purchased merchandise from Boden Company for $6,000 under credit terms of 1/15, n/30, FOB shipping point, invoice dated July 1. Jul. 2 Sold merchandise to Creek Co. for $900 under credit terms of 2/10, n/60, FOB shipping point, invoice dated July 2. The merchandise had cost $500. Jul. 3 Paid $125 cash for freight charges on the purchase of July 1. Jul. 8 Sold merchandise that had cost $1,300 for $1,700 cash. Jul. 9 Purchased merchandise from Leight Co. for $2,200 under credit terms of 2/15, n/60, FOB destination, invoice dated July 9. Jul. 11 Returned $200 of merchandise purchased on July 9 from Leight Co. and debited its account payable for that amount. Jul. 12 Received the balance due from Creek Co. for the invoice dated July 2, net of the discount. Jul. 16 Paid the balance due to Boden Company within the discount period. Jul. 19 Sold merchandise that cost $800 to Art Co. for $1,200 under credit terms of 2/15, n/60, FOB shipping point, invoice dated July 19. Jul. 21 Gave a price reduction (allowance) of $100 to Art Co. for merchandise sold on July 19 and credited Art's accounts receivable for that amount. Jul. 24 Paid Leight Co. the balance due, net of discount. Jul. 30 Received the balance due from Art Co. for the invoice dated July 19, net of discount. Jul. 31 Sold merchandise that cost $4,800 to Creek Co. for $7,000 under credit terms of 2/10, n/60, FOB shipping point, invoice dated July 31. 10 Jul 16 6,000 Accounts payable - Boden Merchandise inventory 0 60 5,940 11 Jul 19 1,200 Accounts receivable - Art Sales 1,200 12 Jul 19 800 Cost of goods sold Merchandise inventory OO 800 13 Jul 21 100 Sales returns and allowances Accounts receivable - Art 100 Dovolo 14 Jul 24 2,000 Accounts payable - Leight Merchandise inventory Cash 40 1,960 15 Jul 30 400 x Cash Sales discounts Accounts receivable - Art volo 16 X 784 X 16 Jul 31 7,000 Accounts receivable - Creek Sales 7,000 17 Jul 31 4,800 Cost of goods sold Merchandise inventory 4,800