GWD两段式，打救一下！

Xiaotongdi

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.

答案是E！
可是我自己写了一下，第一个事实是A不够H普遍，第二个事实是有A的人里有多于95%的人有H，那么这能说明有H的人里有少于95%的人有A？不懂耶！

sorcerer

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.

答案是E！
可是我自己写了一下，第一个事实是A不够H普遍，第二个事实是有A的人里有多于95%的人有H，那么这能说明有H的人里有少于95%的人有A？不懂耶！

-- by 会员 Xiaotongdi (2011/4/8 22:58:46)

100个A中大于95个同时有H
但如果100个H中95个以上有A
不就不能说明H比A普遍
你可能觉得有一个loop
over 95%，就是比95%大
但E取非，not lower than 95%
就是大于等于95%
如果等于95%
还是可以说明H比A普遍啊
但fact1里面的much less common
就否定了这种极小差别，
所以E还是比较tenable的

sdcar2010

This is a must-be-true question: inference.

Only E is true becasuse A is less common than HF.  Therefore the total number of people who have HF is bigger than that of who have A.  Then it is a simple math problem to calculate the percentages for comparison.

Two hundred people have hay fever.  Among them, one hundred people have asthma. Out of the 100 people who have asthma, 95 of them have hay fever, in other words, 95% of the people who have asthma also have hay fever.

Then out of the 200 people who have hay fever, again 95 of them have asthma.  Translation: only 47.5% of the people who have hay fever also have asthma.

Simple math.

小唯唯

This is a must-be-true question: inference.

Only E is true becasuse A is less common than HF.  Therefore the total number of people who have HF is bigger than that of who have A.  Then it is a simple math problem to calculate the percentages for comparison.

Two hundred people have hay fever.  One hundred people have asthma. Out of the 100 people who have asthma, 95 of them have hay fever, in other words, 95% of the people who have asthma also have hay fever.

Then out of the 200 people who have hay fever, again 95 of them have asthma.  Translation: only 47.5% of the people who have hay fever also have asthma.

Simple math.

-- by 会员 sdcar2010 (2011/4/9 7:46:10)

醍醐……

天池居士

[quote]
This is a must-be-true question: inference.

Only E is true becasuse A is less common than HF.  Therefore the total number of people who have HF is bigger than that of who have A.  Then it is a simple math problem to calculate the percentages for comparison.

Two hundred people have hay fever.  Among them, one hundred people have asthma. Out of the 100 people who have asthma, 95 of them have hay fever, in other words, 95% of the people who have asthma also have hay fever.

Then out of the 200 people who have hay fever, again 95 of them have asthma.  Translation: only 47.5% of the people who have hay fever also have asthma.

Simple math.

-- by 会员 sdcar2010 (2011/4/9 7:46:10)


好方法啊