求解：OG12-CR48，谢谢

weixiushiwansui

OG12 48
OG11-50
If the county continues to collect residential trash at
current levels, landfills will soon be overflowing and
parkland will need to be used in order to create more
space. Charging each household a fee for each pound
of trash it puts out for collection will induce residents
to reduce the amount of trash they create; this charge
will therefore protect the remaining county parkland.

Which of the following is an assumption made in drawing the conclusion above?
(A) Residents will reduce the amount of trash they put out for collection by reducing the number of products they buy.
(B) The collection fee will not significantly affect the purchasing power of most residents, even if their house holds do not reduce the amount of trash they put out.
(C) The collection fee will not induce residents to  dump their trash in the parklands illegally.
(D) The beauty of county parkland is an important issue for most of the county’s residents.
(E) Landfills outside the county’s borders could be used as dumping sites for the county’s trash.

正解是C
我选A，为什么不对？

我的理解是：收费的目的是为了减少垃圾（reduce the amount of trash they create）。那么追究根本的，只有少买不必要的东西，少消耗，垃圾才会少啊。

求解，谢谢！！

huangsiyan

Choice A is not REQUIRED for the argument to hold. For your arugment "那么追究根本的，只有少买不必要的东西，少消耗，垃圾才会少啊" to hold,  the residents HAVE to 1) feel the pain of the elevated trash fee; 2) obey the law and do not dispose their trash to their neighbor's lawn or other places. The latter is answer C. Therefore answer A also depends on Answer C.

Necessary assumption. Use negation. If you negate A, the argument still holds. If you ngeate C, the argument falls apart.

weixiushiwansui

thank you!

zhouyeying

根据lawyer分析，该题是条件型结论。
答案C的作用是“排除充分条件出现，必要条件不出现”。不是很理解，能否解释一下？
谢谢

alicejingli

If A --> B, then A --> C.

Remove all answer choices which would NOT lead to A --> C, when A --> B is fulfilled.

foreverluke

as for this question:
A is " Charging each household a fee for each pound of trash "
B is "induce residents to reduce the amount of trash they create"
C is "protect the remaining county parkland."

if A-->B, then A-->C. Is that correct?

weixiushiwansui

消化一下谢谢