继续请教PREP题（3）---一定要51！

slfxiaobai

A store purchased 20 coats that each cost an equal amount and then sold each of the 20 coats at an equal price. What was the store's gross profit on the 20 coats?
1) If the selling price per coat had been twice as much, the store's gross profit on the 20 coats would have been $2,400.
2) If the selling price per coat had been $2 more, the store's gross profit on the 20 coats would have been $440

这题KEY是B，为什么不是D呢？

richard243635

设原价p，售价s。题目求20(s-p)=？
2 可以得出20(s+2-p)=440。化简后得20(s-p)=440-40=400，充分
1 可以得出 20(2s-p)=2400，但20(s-p)=？做不出来吧。

slfxiaobai

1) If the selling price per coat had been twice as much, the store's gross profit on the 20 coats would have been $2,400.

这句话的意思是“如果假设售价是实际售价的2倍，那么毛利就是￥2400”吗？

难怪我觉得奇怪，明明毛利$2400都列出来了还8行...