A certain one-day seminar consisted of a morning session and an afternoon session.If each of the 128 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.

答案是B

我想选C

想问如果选B，求得的只是一个比例不是具体数字啊

文中的at least 128怎么利用呢？

谢谢解答！

B

注意题目最后的only。 7/8参加下午会的也包括了上下午都参加的人，所以可以推出只参加上午会的是1/8，也就是128*（1/8）=16人。

128 attended at least one of the two sessions不是at least 128 ！