求助：prep07 cr1-12题对C选项的解答

esther小冰

Finding of a survey of Systems magazine subscribers: Thirty percent of all merchandise orders placed by subscribersin response to advertisements in the magazine last year were placed by subscribers under age thirty-five.

Finding of a survey of advertisers in Systems magazine:Most of the merchandise orders placed in response to advertisements in Systems last year were placed by people under age thirty-five.

For both of the findings to be accurate, which of the followingmust be true?

(A) More subscribers to Systems who have never ordered merchandise in response to advertisements in the magazine are age thirty-five or over than are under age thirty-five.

(B) Among subscribers to Systems, the proportion who are under age thirty-five was considerably lower last year than it is now.

(C) Most merchandise orders placed in response to advertisements in Systems last year were placed by Systems subscribers over age thirty-five.

(D) Last year, the average dollar amount of merchandise orders placed was less for subscribers under age thirty-five than for those age thirty-five or over.

(E) Last year many people who placed orders for merchandise in response to advertisements in Systems were not subscribers to the magazine.

困惑C选项：
C.在看了S杂志广告后产生的购物订单中，大多数的订单来自于超过35岁订阅者
而通过调查1，我们可以知道：30％的订单来自于35岁以下订阅者,那么可以反过来推出70%的订单来自于超过35岁的订阅者，这样不就与C的答案相符了吗？？？
求助啊~~~

HarrisZheng

那么可以反过来推出70%的订单来自于超过35岁的订阅者--------这个地方错了



只能说70%不来自35岁以下订阅者  （可以是来自35以上订阅者，也可以来自非订阅者）

取非不是绝对相反  比如不黑 并不表示白 不美 并不表示丑

Doriskk

我也是选了C，现在好像有点明白了