Exercise 2: Aging of A/R Ethan Inc. uses the aging approach to estimate bad debt expense. The balance of each A/R is aged on the basis of three time periods as follows at Dec. 31, 2018: (1) Not yet due $12,000; (2) up to 120 days past due $5,000; and (3) more than 120 days past due $3,000. Experience has shown that for each age group, the average loss rate on the amount of the receivable at year-end due to uncollectability is (1) 2%; (2) 10%; (3) 30%, respectively. Assume at Jan. 1, 2018, the allowance for doubtful accounts had $500 credit balance. Total write-off during 2018 was $1500. (a) Record write-off (b) Record adjusting entry at the end of 2018