PS:GWD-9里面的数学错题。当时觉得太搞了,没有思路,静静地倒能想明白。 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. OA IS A. 思路:题目问100人中有几人都投了F (A大类的)投F的人包括:投1个F ,1个UF的; 1个F,1个NS的; 2个F的 (当成B大类吧) 其余投票的情况是:2个都是NS的, 2个都是UF的 1个UF,1个NS的 条件1说 :B大类的人一共40个,则A大类的一共60人 根据韦恩图,both F 的人数为40+30-60=10 选A. (ps.1月数学JJ有一题类似,是说什么几种口味排序。。如果我做的话。。只会这种全部排列出来的方法。。。咳咳,这种题当场能做出来的话,应该是头脑非常清醒的人吧。)