GWD-18-Q15

frankman

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.

请问下NN，为什么选择E，为什么排除CD？用韦恩图可以解决吗？

stavan

这个题目用不到韦恩图吧...当然也是可以画画..呵呵..

题目没有涉及A和HF占总人口的比例, 所以无法推出没有A或HF占total population的比例, C排除

设A有100人, 有HF的有10000人, 其中95人有A和HF, 在这种情况下, 满足题目全部条件, 但是无法退出D, 所以D不对

E..说老实话, 这个也不是很非常严密...但是既然A 是much less common than HF, 如果A有100, HF肯定不能是101,

就算HF有106, 100和106, 这都算不上是much less吧..在这种情况下, 就算所有的A都有HF, 100/106<95%,所以E肯定是对的

这个选项不严密的地方是没有定义什么是much less common, 不过...稍微用一点常识...还算是可以说的过去的...

nirvana_35

smallmole

juvenren

看了这个解释泪奔了，也就是第二个fact就是拿来糊弄人的啊！明显不可能哈！
其实这题可以用概率论的知识推导出来的：
条件1：P（A）<(B)
条件2：P（B/A)（也就是在A发生的前提条件下，B发生的概率）=P(AB)除以P（A）=0.95
而E选项是求P（A/B)=P(AB）除以P(B)
由于P(A)<(B),所以E选项小于0.95