Book A shows the balance as of December 31, 1987 as follows: Accounts receivable $627,500 Deferred Gross Profit (before adjustment) 76.000 Analysis and age determination of trade receivables shows Ordinary trade receivables $415,000 Accounts receivable installments in 1986 32,500 Accounts receivable installments in 1987 180.000 Installment sales in 1986 were made at 30% above cost of goods sold; 1987 at 33 1/3% above cost of goods sold Prepare the journal entries needed to adjust the estimated deferred gross profit at the end of 1987