求教GWD 1-14

小小照妖镜

That the application of new technology can increase the productivity of existing coal mines is demonstrated by the case of Tribnia’s coalindustry.  Coaloutputperminerin Tribnia is double what it was five years ago, even though no new mines have opened.

Which of the following can be properly concluded from the statement about coaloutputperminerin the passage?

A.    If the number of miners working in Tribnian coal mines has remained constant in the past five years, Tribnia’s total coal production has doubled in that period of time.
B.    Any individual Tribnian coal mine that achieved an increase in overall outputin the past five years has also experienced an increase inoutputperminer.
C.    If any new coal mines had opened in Tribnia in the past five years, then the increase inoutputperminer would have been even greater than it actually was.
D.    If any individual Tribnian coal mine has not increased its outputperminerin the past five years, then that mine’s overall output has declined or remained constant.
E.    In Tribnia the cost of producing a given quantity of coal has declined over the past five years.

在A和D中间徘徊了好久，最终选了D，可是答案是A啊！！
为什么D错了呢？
其他贴里面都没有解释D错的原意啊。。

sanlingjie

从别的地方摘过来的：
nope.

see above -- it's possible that the mines added workers.

if a mine added workers, then its TOTAL OUTPUT could increase despite a decrease in the per-worker output.
(i.e., think about 100 workers producing 3 units each, vs. 200 workers producing 2 units each.)

can't prove the statement.

amare

我选的是C，错在哪儿呢？

sanlingjie

我选的是C，错在哪儿呢？

-- by 会员 amare (2011/7/16 22:23:56)

For C, because  the number of miners working in Tribnian coal mines is indefinite,
output per miner=total output/total miners, even the number of mines increased may lead to the increase of the total output, but the total miners might also get an increase, therefore, we cannot get a conclusion on the output per miner, just because there are two variables in the foresaid formula.

franciscomatt

我觉得是A啊。。

sanlingjie

我觉得是A啊。。

-- by 会员 franciscomatt (2011/7/18 6:37:46)

Correct!

huiyuforever

题目说一句double了，D说每double的情况，不是扯蛋么。。。C同理，人家没开新矿，无关嘛

ellenchuwang

对这个题目正确理解的关键点在于对于“any individul...”的理解上，在这里应该理解为“任意一个单独的...”。

D：如果在过去5年中，有任意一个采矿者的产量没有提高，那么整体的产量就会下降或者保持不变。
当然是错误的。
同样的错误也出现在B选项中。整体产量double，同时没有新的采矿公司成立；并不意味着现有的任意一个单独的采矿公司产量都增加。

以上是我的理解，欢迎批评指正哈。

小小照妖镜

对这个题目正确理解的关键点在于对于“any individul...”的理解上，在这里应该理解为“任意一个单独的...”。

D：如果在过去5年中，有任意一个采矿者的产量没有提高，那么整体的产量就会下降或者保持不变。
当然是错误的。
同样的错误也出现在B选项中。整体产量double，同时没有新的采矿公司成立；并不意味着现有的任意一个单独的采矿公司产量都增加。

以上是我的理解，欢迎批评指正哈。

-- by 会员 ellenchuwang (2011/7/23 14:13:58)

有道理！