出现表格题！

Xiaotongdi

	Favorable	Unfavorable	Not Sure
Candidate M	40	20	40
Candidate N	30	35	35

The table above shows the results of a survey of 100 voters each responded “favorable” or “unfavorable” or “not sure” when asked about their impressions of candidate M and of candidate N.What was the number of voters who responded “favorable” for both candidates?
(1)The number of voters who did not respond “favorable” for either candidate was 40.
(2)The number of voters who responded “unfavorable” for both candidates was 10.

答案是A！其实这题没读懂！

Avengeryzc

100个调查者进行民主选举，问你对m和n都有好感的投票人有几个~
（1）对于m和n一个都不投喜欢的人有40个。也就是这40个人，不是投不喜欢就是投not sure
（2）对m和n都讨厌的人有10个
条件1显然是答案
2票中起码有一票喜欢的有60人，30+40-60=10
so 选a

红红的云

for statement 1 ，

There are 3 views 1) favorable 2)Unfavourable 3)Not sure
     

"The number of voters who did not respond “favorable” for either candidate was 40."

40 includes both unfavourable & not sure as did not respond “favorable” means who are not favourable so that includes both Unfavourable & Not sure.

>>>>> 60 is the number of voters who respond favorable m or n:MuN.

question: MnN ?

MnN=m+n-MuN= 40+30-60=10          sufficient

for statement 2：

The number of voters who responded “unfavorable” for both candidates was 10。 combined with information given in the table。 we can know the number of  responding unfavorable 20 +30 -10=40.
which means the total number of respond favorable ，  unsure is 100-40=60 。
no further information given to tell the favorable from the unsure


However， because MnN=m+n-MuN  ，we have to know mUn  to reach the answer since we know m and n， but we cannot know MUN from the statement 2， so insufficient

红红的云

别人的解释：
here's an  link

http://www.postimage.org/image.php?v=gx1ffBD9


the answer still mistakenly says 'B' on the bottom of the page. (it's supposed to be (a))

爱吃巧克力

表格要竖着看
the number of voters who did not respond “favorable” for either candidate was 40.表示投favorable的共有60人。而表格里两个人的favorable的总票数为70，说明有10个人给MN都投了f，充分！
The number of voters who responded “unfavorable” for both candidates was 10表示10个人给MN都投了unf，单独给给N和M投unf 的人数，求不出关于f的，不充分