求教 GWD 18-12 BY LIAOXUN (原连接没有给出明确解答)再次求教!

gwd18-15

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.

参考答案是E，请问如何推导出E是正确的?

第一句是想说得A的人数比HF的人要少,第二句你画一下交集,再结合第一句就能得到E.

Since Asthma is a less comman ailment than Hay fever. Suppose 100 persons have Asthma, 101 persons have Hay fever. 95%=95/100, 95 persons out of 100 persons have both Asthma and Hay fever.The percentage of person who have Hay fever also have Asthma would be: 95/101. 95/101 is less than 95/100.Hence the answer is E.