【求助一道DS集合题】

Joyce74

A certain one-day seminar consisted of a morning session and an afternoon session. If each of
the 128 people attending the seminar attended at least one of the two sessions, how many of
the people attended the morning session only?

(1)3/4 of the people attended both sessions.
(2)7/8 of the people attended the afternoon session.

这道题选B
但不明白的是条件2中，1/8的人应该是参加morning session的人啊，但是morning session的人=只参加morning session的人+both参加了morning & afternoon session的人啊。题目中问的是only 参加morning session的人啊

Joyce74

lyxxuan 发表于 2018-1-5 10:42
总人数-attend afternoon=only attend morning

画一个图就可以看出来了！

恩恩 谢谢Thanks♪(･ω･)ﾉ

lyxxuan

总人数-attend afternoon=only attend morning

画一个图就可以看出来了！