成會 有關materials的問題 - 會計

On January 1, the general ledger of Jackson Company contained the following
accounts and balances:


finished goods.......................$32,500
work in process...................... 7,500
materials............................ 21,500
^^^^^^^


Details of inventories are:(January 1)

finished goods inventories:$32,500
work in process inventories:
job 1 job 2
------- ---------
direct materials $2,500 $ 600
direct labor 2,000 1,000
factory overhead applied 1,000 400
------- -------
totals $5,500 $2,000


materials inventory:$22,000
^^^^^^^
請問為甚麼是$22,000，而不是$21,500呢?!
既然是上面inventories的明細，那應該等於$21,500阿

懇請大大解答><
謝謝!!

:)

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