Finding unknown balances. An auditor for Canada Revenue Agency is trying to reconstruct some partially destroyed records of two taxpayers. For each case in the accompanying list, find the unknowns designated by capital letters (figures are in thousands).

Case 1 Case 2 Accounts receivable, December 31, 2007 $ 7,200 $ 2,520 Cost of goods sold A 24,000 Accounts payable,January 1, 2007 3,600 2,040 Accounts payable, December 31, 2007 2,160 1,800 Finished goods inventory, December 31, 2007 B 6,360 Gross margin 13,560 C Work in process,January 1, 2007 0 960 Work in process, December 31, 2007 0 3,600 Finished goods inventory,January 1, 2007 4,800 4,800 Direct materials used 9,600 14,400 Direct manufacturing labour 3,600 6,000 Indirect manufacturing costs 8,400 D Purchases of direct material 10,800 8,400 Revenues 38,400 38,160 AN INTRODUCTION TO COST Accounts receivable,January 1, 2007 2,400 1,680