[求助]Prep-1-23 GMATprep 1-23

lg77xx

23.  (29107-!-item-!-188;#058&003854)解释

From 1978 to 1988, beverage containers accounted for a steadily decreasing percentage of the total weight of household garbage in the United States.  The increasingly widespread practice of recycling aluminum and glass was responsible for most of this decline.  However, although aluminum recycling was more widely practiced in this period than glass recycling, it was found that the weight of glass bottles in household garbage declined by a greater percentage than the weight of aluminum cans. 

Which of the following, if true of the United States in the period 1978 to 1988, most helps to account for the finding? 

(A) Glass bottles are significantly heavier than aluminum cans of comparable size.

(B) Recycled aluminum cans were almost all beverage containers, but a significant fraction of the recycled glass bottles had contained products other than beverages.

(C) Manufacturers replaced many glass bottles, but few aluminum cans, with plastic containers.

(D) The total weight of glass bottles purchased by households increased at a slightly faster rate than the total weight of aluminum cans.

(E) In many areas, glass bottles had to be sorted by color of the glass before being recycled, whereas aluminum cans required no sorting.

饮料瓶子在垃圾中所占比例逐渐减少，原因是玻璃和铝制品的回收深入人心。然而，虽然铝的回收工作比玻璃的回收开展得更加深入，但是玻璃占垃圾总重的比例下降却要比铝制品占垃圾的总重快。

请解释这样的一个现象：

A，玻璃瓶子比铝制瓶子重

B，铝制的几乎都是饮料瓶子，玻璃的还有其他瓶子——无关

C，制造商更多的使用塑料来替代玻璃瓶而不是饮料瓶

D，Total weight of glass bottles purchased…——无关

E，垃圾分类——无关

正确答案是C，

我觉得可以解释，但是A为什么不行？

[此贴子已经被作者于2007-5-8 13:53:49编辑过]

lg77xx

up!牛牛捏？

lxzmonica

我不是牛牛,但是说说我的想法, 我觉得所谓的比较,是玻璃现在和玻璃原来所占垃圾总重的差,与比铝现在和铝原来占垃圾总重的差比较,同一时间段,玻璃由占垃圾总重的10%到1%,而铝则由20%到15%.下降比例9%>1%.所以原因与重量本身无关. 你觉得呢?

ivysopher

agree to lxzmonica; here is another way to explain:

premise: weight of glass heavier than plastic

means: even they(glass&plastic)decresed with same degree,

the result is: weight decrease of glass > weight decrease of Al

so: we don't know what kind of degree of decrease that glass has achieved:if it greater or equal or even smaller than what Al has had.

miffycn

不是NN 但是我也做了这题 开始跟你感觉一样选A

但是回归题目,说it was found that the weight of
            glass bottles in household garbage declined by a greater percentage than the weight of aluminum cans. 

是从总量上看,bottles   A只是从单个瓶子上看 所以 不能解释.

请你也看看我的问题吧   也是prep的~~~

jeanyjhl

以前的討論

http://forum.chasedream.com/dispbbs.asp?boardid=24&replyid=2338066&id=249647&page=1&skin=0&Star=2

(A)主要還是絕對值和相對值的關係 (percentage)..

類似lxzmonica 的說法

因 percentage 是相對值 和絕對重量無關

故A 為 irrelevant 選項

[此贴子已经被作者于2008-7-17 6:40:59编辑过]

sausau

??????????///

ivymxy

up

dawnssing

exactly!

24lam

还是不太懂，
因为玻璃的重量重，所以即使较少玻璃瓶的减少也会导致总垃圾重量的大幅减少；
而铝制瓶因为比较轻，所以即使铝制瓶回收的更多，可能并不导致总垃圾重量的大幅减少。

如果说原来垃圾总重量是100KG，
一个玻璃瓶3KG，15个玻璃瓶，45KG，
一个铝制瓶1KG，30个铝制瓶，30KG。

那么接下来减少了10个玻璃瓶，30KG，和20个铝制瓶，20KG，
现在的垃圾总重量就是50KG，有5个玻璃瓶，15KG，和10个铝制瓶，10KG；

原来玻璃瓶的百分比是45/100=45%，铝制瓶的百分比是30/100=30%；
现在玻璃瓶的百分比是15/50=30%，铝制瓶的百分比是10/50=20%；

所以玻璃瓶下降的百分比（45%-30%=15%）>铝制瓶下降的百分比（30%-20%=10%）

所以A是对的阿~！！ T T 求指导，好难的题阿。。。。