请问一个题目的提干怎么理解?

Finding of a survey of Systems magazine subscribers: Thirty percent of all merchandise orders placed by subscribers in 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 following must 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.    (11/02/2004)

题目不全 我觉得提干是全的 偶的理解出问题了 请指教!!!

订阅者包括2种人，1，前年的subscribers 续顶，2，新人。第一句话实际就是说1的

明白了这个，这就是个数学题。

B,  than it is now.排除，

顶

finding 1:订阅者中订货的人中30%是30岁以下的。

finding2:订货的人中大部分是30岁以下的。

估计很容易看清楚了