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) 34 of the people attended both sessions.
(2) 78 of the people attended the afternoon session.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
答案没错,因为说了至少参加一场课程, 画出文氏图就发现,只要下午没上课的一定都是只去上午上课的人。
错了……
文氏图,2个圆,条件1很明显不满足,条件2说明,剩下的1/8是只参加了上午场,充分。
这一题答案有错,应该是C
这题答案并没错,条件二说的是八分之七的人参加了下午场,这里包括只参加下午场和同时参加上下午场的人,所以只参加上午场的人就是剩余的八分之一
难道说八分之七是指128的八分之七,这也太摸棱两可了,为什么不能指是所有人,包括没参加的
题就是在讨论到场的人如何了和不参加的人没有关系,所以在这里128就是所有人
老师,您好!
如果这样理解,为什么题目不说:“7/8 of the people attended the afternoon session only"?
条件2是问题取反,是不是应该表述一样呢?
C为啥错,求解释 谢谢
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