Record the following transactions on the books of Essex Corp., which uses a perpetual inventory system.

(a) On July 1, Essex Corp. sold merchandise on account to Cambridge Inc. for $42,000, terms 2/10, n/30. The cost of the merchandise sold was $30,000.

(b) On July 8, Cambridge returned merchandise worth $7,200 to Essex. Its original cost was $4,320. The merchandise was restored to inventory.

(c) On July 9, Cambridge paid for the merchandise.

(d) Assume now that Cambridge did not pay on July 9, as indicated in transaction (c). At the end of August, Essex added one month's interest to Cambridge's account for the overdue receivable. Essex charges 24% per year on overdue accounts.

Round calculations to the nearest dollar.