返回列表 发帖

问一道逻辑题(陈向东的逻辑推理)

这道题是陈向东编的GMAT逻辑推理 书中的,因为找不到有关这本书中题目的讨论,所以新开一贴,麻烦nn们帮忙解释下。
P503  
10. A recent survey showed that 50 percent of people polled believe that elected officials should resign if indicted for a crime, whereas 35 percent believe that elected officials should resign only if they are convicted of  a crime. Therefore, more people believe that elected officials should resign if indicted than believe that they should resign if convicted.
The reasoning above is flawed because it
A. draws a conclusion about the population in general based only o a sample of that population
B. confuses a sufficient condition with a required condition
C. is based on an ambiguity of one of its terms
D. draws a conclusion about a specific belief based on responses to queries about two different specific beliefs
E. contains permises that cannot all be true
答案是b, 我选了a
实在想不通b所谓的充分条件,必要条件是怎么对应文中的推理?
收藏 分享

因为PREMISE部分是recent study,但是结论是普遍性的,所以一般不可以推特殊

TOP

显然50%和35%的比较基数没有说明。如果基础一样则能得出结论。显然文中说明的只是一个必要条件,基数相同是另一个必要条件;文中直接得出结论犯了这样的错误,把必要条件当成是充分条件。

TOP

谢谢楼上阿。

一下子明白了。

TOP

indicted for a crime(被起诉)是be convicted a crime(被定罪)的必要条件。一定是先被起诉,再被定罪。所以原文有问题。前提是35%认为官员应该辞职ONLY IF他们被定罪,到了结论ONLY IF没了,那么,认为被定罪该辞职的人,就应该是50%+35%=85%,因为认为起诉就该辞职的人,当然认为被定罪的该辞职。那么,实际结论应该与原文结论相反。

所以,原文混淆了充分与必要条件,将indicted与convicted两者的推导顺序弄反了,才会得出那样的结果。

TOP

帮顶,看不出B项和题目的关系。莫非,题目错了?

TOP

返回列表

站长推荐 关闭


美国top10 MBA VIP申请服务

自2003年开始提供 MBA 申请服务以来,保持着90% 以上的成功率,其中Top10 MBA服务成功率更是高达95%


查看