询问：老prep 第12题 （NUMBER AND PERCENTAGE)

jodieluo

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.
(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.
不懂要怎么做这类题，求指导

jodieluo

HarrisZheng

from MahattanGMAT

in this problem:
of the orders placed by subscribers in response to ads, only 30% were from the under-35 crowd.
of the orders placed by anyone in response to ads, over 50% were from the under-35 crowd.
there's the discrepancy.

therefore, you need an answer choice that explains where all the extra orders in the 'anyone' category. this means in the 'anyone category and not in the 'subscribers' category; no more, no less. that's exactly what is described in choice e.

jodieluo

万分感谢~