求教GWD-9-13(好像没有讨论过)

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?

1. Hay fever is a prerequisite for the development of asthma

2. Asthma is a prerequisite for the development of hay fever

3. Those who have neither hay fever nor asthma comprise less than 5 percent of the total population

4. 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.

答案为E,我选B. 不明白，请那位高人指点一下。谢谢！！！

画个韦氏图就知道了

两者相交处假设为95, 有A无H的有5, 而题目说A<H,所以有H无A的大于5,假设为6,

所以

95/(95+6)<95%

很形象，现在明白了，谢谢sunjie38！