(a) On January 6, Stegner Co. sells merchandise on account to Molina Inc. for $7,000, terms 2/10, n/30. On January 16, Molina Inc. pays the amount due. Prepare the entries on Stegner's books to record the sale and related collection.

(b) On January 10, Jill Flynn uses her Calhoun Co. credit card to purchase merchandise from Calhoun Co. for $9,000. On February 10, Flynn is billed for the amount due of $9,000. On February 12, Flynn pays $4,000 on the balance due. On March 10, Flynn is billed for the amount due, including interest at 2% per month on the unpaid balance as of February 12. Prepare the entries on Calhoun Co.'s books related to the transactions that occurred on January 10, February 12, and March 10.