帮我看看如何算depreciation equipment, disposal, 如何

pierce

题目是这样的：Equipment: cost, 85,000; accumulated depreciation: 32,000. NBV: 53,000

the equipment was all purchased on 1.1.04 and at that time had an estimated scrap value of $5,000. In january 2008 half theequipment by value was sold for $28,000. 现在要算disposal, 怎么算呢？