In 2017, the D.H. Lawrence Co. had credit sales of $750,000 and granted sales discounts of $15,000. On Jan. 1, 2017, Allowance for Doubtful Accounts had a credit balance of $18,000. During 2017, $30,000 of uncollectible accounts receivable were written off. Past experience indicates that 3% of net credit sales become uncollectible. What should be the adjusted balance of Allowance for Doubtful Accounts at December 31, 2017?