求助一道GWD数学

静夜

                           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 candidate?

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.

一点思路都没有,请教一下各位高手!谢谢!

angelwds

LZ 答案是A么？

静夜

是的,应该怎么解?谢谢!

angelwds

题目意思是，M,N两个人竞选嘛，调查了100个人，问他们对这两个人的意见，支持，不支持，或者，不清楚。

问有多少人同时支持两个人。

（1）没投支持票的有40人

也就是说投了支持票的有60人

由已知，投M+N的有30+40人

也就是说，支持两个人的有 30+40-60=10人

(2)嘛。。求不出来。。

静夜

明白了,多谢哈~~