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标题: [問題]Pre-P2-Ds 210 [打印本页]

作者: amywliang 时间: 2008-2-12 03:43
标题: [問題]Pre-P2-Ds 210

210. 20513-!-item-!-187;#058&013256

For each order, a mail-order bookseller charges a fixed processing fee and an additional shipping fee for each book in the order. Rajeev placed five different orders with this bookseller--an order for 1 book in January, an order for 2 books in February, an order for 3 books in March, an order for 4 books in April, and an order for 5 books in May. What was the total of Rajeev's processing and shipping fees for these five orders?

(1) Rajeev's processing and shipping fees were $1.00 more for his order in March than for his order in January.

(2) The total of Rajeev's shipping fees for the five orders was $7.50.

ans:E

為什麼不是C啦 (1)+(2)不是可以解聯立了嗎？？？

作者: howren 时间: 2008-2-12 05:23

我怎么觉着应选A呀，因为3（P+S）=1*（P+S）+1

P+S=1/2（P、S分别为加工费和运输费）

这样，1倍的P+S+2倍的。。。+3倍的。。。。+5倍的（P+S）=。。。。

作者: 李月桃儿 时间: 2014-8-6 22:51

howren 发表于 2008-2-12 05:23
我怎么觉着应选A呀，因为3（P+S）=1*（P+S）+1P+S=1/2（P、S分别为加工费和运输费）这样，1倍的P+S+2倍的。 ...

答案是对的，应该选E。
由（1）知：p+3s-1=p+s 得出s=0.5
由（2）知：s+2s+3s+4s+5s=7.5 得出s=0.5 与（1）一样，只求得了S ，p仍然是未知，
所以选E。

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