这道GWD CR谁做过的，能帮忙解释一下吗？

dreambuilder

Q40:

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.

为什么选E呢？想不通啊

prayer

Q40:

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.

为什么选E呢？想不通啊

-- by 会员 dreambuilder (2010/1/8 3:48:47)

有哮喘的病人中95%也有黄热病。

AB这个必要条件推不出来的；

C文章中没有提到total population中病人占的比例，所以此选项推不出来不生病的人都比例；

D黄热病的病人有多少不知道，所以只得黄热病的人比都得病的多少不知道；

E：同时得两种病的病人少于95%，这是肯定的，因为两种病都有的人占哮喘病人的95%，还有不得病的人和只有黄热病的人，所以肯定小于95%

ryanyhu

画一个集合图，一个方框里面两个相交的圆那种，然后标上文中提到的比例，就很容易看出来了