请教OG-DS-129

applebees

129, At the beginning of last month, a stationary store had in stock 250 writing pads, which had cost the store $0.75 each. during the same month, teh store made only one purchase of writing pads. What was the total amonut spent by the store on the writing pads it had in stock at the end of last month?

1) Last month the store purchased 150 wriitng pads for $0.80 each.
2) Last month the total revenue from the sale of writing pads was $180.

Ans:E, i choose C

2)讲的revenue难道 不是the number of sale X the sale price? 为什么不对呢？

谢谢。

ghfgss231

同问这道OG的DS题。

the total amount spent on the writing pads =刚开始就有的pads的量*单价1+购买进的pads的量*单价2 -销售这些pads的收入

题目已给了刚开始就有的pads的量*单价1

条件1给出了购买进的pads的量*单价2

条件2给出了销售这些pads的收入，

那么答案就该是C而不是E啊。

有人能解释一下吗？谢谢了。