GWD 逻辑题求助

sunflower88

GWD-9-Q13:
Fact: Asthma, a bronchial condition, is much less common ailment than hay fever, an allergic inflammation of the nasal passages.
Fact: over 95 percent of people who have asthma also suffer from hay fever.
If the information given as facts above is true, which of the following must also be true?

A.    Hay fever is a prerequisite for the development of asthma
B.    Asthma is a prerequisite for the development of hay fever
C.    Those who have neither hay fever nor asthma comprise less than 5 percent of the total population
D.    The number of people who have both of these ailments is greater than the number of people who have only one of them
E.    The percentage of people suffering from hay fever who also have asthma is lower than 95 percent.
E是正确的，其他几个选项怎么排除呀，思路是什么？
帮忙解答一下，谢谢啦

sunflower88

THANKS

laurawang2234

其实在草稿纸上画两个交叉的圆，一个大圆代表HAY FEVER（X)，一个小圆是ASTHMA(Y)，中间交叉的部分就是HAFY FEVER-ASTHMA(Z)。
用数学公式表示就是
Z/Y>95%，因为X>Y，所以很明显Z/X<95%。
其实大家照我说的画个图就很直观了。很简单的数学分析。

sunflower88

恩，谢谢了

pangpangshin

fact: asthma比hay fever少见的多
fact: 有asthma的人95%都有hay fever

以上facts中，完全没有关于它们之间先后关系的明确论述（谁引起谁），所以A和B都可以排除。
C的话，因为原文与total population无关，所以也排除。
D的意思错的比较明显：得某一种病并不会必定得另一种，则两种都得的人肯定要小于只得一种的之和。

而E是直接从原题推出的：有asthma的人又有hay fever的是95%，而得asthma比得hay fever要难很多（= =），因此得hay fever里的又得asthma的就应该比95%少