OG12 107 跪求大牛指导

kokia561 · 发表于 2012-2-14 22:46:31

107. Last year all refuse collected byShelbyville city services was incinerated（焚烧）. This incineration generated a large quantity of residual ash. Inorder to reduce the amount of residual ash Shelbyville generates this year tohalf of last year’s total, the city has revamped its collection program. Thisyear city services will separate for recycling enough refuse to reduce thenumber of truckloads of refuse to be incinerated to half of last year’s number.
Which of the following is required for the revamped collection program to achieve its aim?
(A) This year, no materials that cityservices could separate for recycling will be incinerated.
(B) Separating recyclable materials frommaterials to be incinerated will cost Shelbyville less than half what it costlast year to dispose of the residual ash.
(C)Refuse collected by city services willcontain a larger proportion of recyclable materials this year than it did lastyear.
(D) The refuse incinerated this year willgenerate no more residual ash per truckload incinerated than did the refuse incineratedlast year.
(E) The total quantity of refuse collectedby Shelbyville city services this year will be no greater than that collectedlast year.
此题答案是D。
可是为什么不选择C呢，我觉得如果说垃圾这个部分可回收的增加了，那么被燃烧的部分就会减少，那么不久可以达到目的了吗？
多谢大家帮忙，感觉老是绕不过弯来选项极具迷惑性

sdcar2010 · 发表于 2012-2-15 04:29:38

The problem with C) is that it is not necessary. Even if the recyclable portion shinks this year vs. last year, if the total amount of refuse shinks at a larger rate, then the plan still works.

It is a necessary assumption question. Use negation method to find the correct answer choice.

City service will separte enough refuse for recycling purposes in order to reduce the total number of truckloads of refuse sent for inceineration by half. The intent is to convert at least half of the refuse for recycling in order to cut the total amount for incineration/burning in a year.

If you read carefully, you would notice a scope shift from "the amount of residual ash" to "the number of truck loads." For the conclusion to hold, D has to be true, since it connects "amount of ash" to "truckload." What if this year's truck increases its capacity to twice as much as last year? Then the city will end up with equal amount of ash in the end.

h14zpsn · 发表于 2012-2-15 06:43:31

惊现SDCAR大神···一定要在这里留个贴了···

kokia561 · 发表于 2012-2-15 13:16:41

感谢大牛的解释啊。怎么读题目的时候自己会没有这个感觉呢呵呵

OG12 107 跪求大牛指导

所属分类: GMAT考试

正在浏览此版块的会员 ()

浏览过的版块