标题: 【求助一道DS集合题】 [打印本页] 作者: Joyce74 时间: 2018-1-5 10:25 标题: 【求助一道DS集合题】 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.