问一道题：NO.PZ2016012101000157 [ CFA I ]

NO.PZ2016012101000157问题如下A financianalyst is stuing the income statement effeof two alternative preciation metho for a recently acquirepieof equipment. She gathers the following information about the equipment’s expecteproction life anuse:Comparewith the units-of-proction methoof preciation, if the company uses the straight-line methoto preciate the equipment, its net income in Ye1 will most likely be: A.lower. B.higher. C.the same. is correct.If the company uses the straight-line metho the preciation expense will one-fifth (20 percent) of the preciable cost in Ye1. If it uses the units-of-proction metho the preciation expense will 19 percent (2,000/10,500) of the preciable cost in Ye1. Therefore, if the company uses the straight-line metho its preciation expense will higher anits net income will lower.解析题目问相比units-of-proction metho种折旧方法，直线折旧法在第一年的净利润是更高、更低还是相同。直线折旧法是将机器的价值在五年使用年限中平摊，也就是每年折旧20%。工作量法是用当年的产量除以预计总产量算出该年度的折旧比例，第一年的折旧率是2000/10500=19%，小于直线折旧法的20%折旧率。因此直线折旧法的折旧费用更高，净利润因此是更低，A正确。 这个题太坑了，竟然问net income

我感觉我是英语理解的问题，最后一句是想说谁与谁相比，不是说如果用直线法会比用产量法更大么？

    这道题的怎么理解？既然straight 有残值为什么不考虑？是因为题目中没说所以是0？

这里的20%是怎么算出的？