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标题: 狒狒上一道逻辑题目 [打印本页]

作者: miraere 时间: 2009-7-7 15:01
标题: 狒狒上一道逻辑题目

A low-pressure weather system is approaching Plainville; rainfall results from about 70 percent of such systems in the Plainville area. Moreover, the current season, spring, is the time of year in which thundershowers, which sometimes result from low-pressure systems, are most likely to occur in Plainville.

Knowing which one of the following, in addition to the information above, would be most useful for determine the probability that Plainville will have a thundershower soon?

(A) the percentage of thundershowers in Plainville that occur in the spring

(B) the percentage of spring rainfalls in Plainville that are thundershowers

(D) whether low-pressure systems in other areas are associated with rainfall

(E) whether Plainville has more or fewer thundershowers each spring than do near by towns

我选的C，答案给的是B，不晓得为何选B。

作者: xfi883 时间: 2009-7-7 15:15

答案就是C。

文中给出两个条件，1是低压天气将到达，而70%的低压天气导致降雨，2是现在正是1年中雷阵雨最多的季节且雷阵雨有时也是由于低压天气导致；答案（C）给出了低压天气导致雷阵雨的比率，用70%乘以这个比率，就可以得到下雷阵雨的概率了。

作者: miraere 时间: 2009-7-7 15:43

To xfi883 -

谢谢~刚贴的两道题看到你很快帮助回复了。

请问下雨的这个确定是C吗？狒狒给的答案错误啊。

作者: xfi883 时间: 2009-7-7 15:46
我看到网上很多帖子标准答案都是C，而且C确实没问题。所以可能是你的电子版有校对问题。

[此贴子已经被作者于2009-7-7 15:46:08编辑过]

作者: edmundshi 时间: 2009-7-7 18:25

我选的B～

想问一下：

C只给出了低压天气导致雷阵雨的比率，并不代表春季雷阵雨的概率。比如说：雷阵雨在其他三个季度出现的概率总和比春季高，C没给出由于低压导致的春季雷阵雨的比例，而B却给出了啊，拿B给出的比例乘以70%就是“有低压导致春季雷阵雨的概率”吧？

请借鉴一下这几贴的讨论：

http://forum.chasedream.com/dispbbs.asp?boardid=24&replyid=3397609&id=321424&page=1&skin=0&Star=1

http://www.urch.com/forums/gmat-critical-reasoning/117662-low-pressure-weather-system-approaching-2.html

http://www.urch.com/forums/gmat-critical-reasoning/29999-plainville-area.html

[此贴子已经被作者于2009-7-7 18:52:21编辑过]

作者: miraere 时间: 2009-7-8 11:31

谢谢edmundshi的解答。

看了下讨论的贴，又看了看题目，最后觉得应该是B。

知道了RAINFALL和LOW PRESSURE的关系，再知道RAINFALL和THUNDERSHOWER的关系，就能推出LOW PRESSURE情况下THUNDERSHOWER的关系。

好绕的一个题。

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