求助一题！！不好意思总打扰大家学习！！

JGMATJ · 发表于 2011-3-13 16:34:11

请指教弱智都能做对的, 可我就是不对的一题:

Of the students who eat in a certain cafeteria, each student either likes or dislikes lima beans and each student either likes or dislikes brussels sprouts. Of these students, 2/3 dislike lima beans; and of those who dislike lima beans, 3/5 also dislike brussels sprouts. How many of the students like brussels sprouts but dislike lima beans?

1. 120 students eat in the cafeteria.
2. 40 of the students like lima beans.

答案是每个条件都各自充分,比弱智还弱智的我原以为两个一起才充分...

多谢......

backlighting · 发表于 2011-3-13 17:22:39

How many of the students like brussels sprouts but dislike lima beans?
喜欢bs的人中有多少不喜欢lb
不需要求出喜欢bs的有多少
从1得到80 dislike lima beans且这80个人中，48个人dislike Brussels Sprouts ，剩下32个人like bs。答案应该就是32，所以充分。
第二个条件给了40人like lb，占总人数三分之一，得到总人数120，剩下的和1的条件一样了
所以选D

JGMATJ · 发表于 2011-3-13 17:41:27

感激不尽！！！！backlighting真厉害！！！！！
谢谢谢谢谢谢谢谢谢谢谢谢！！！！！！！！！！

wangwei1212 · 发表于 2011-3-13 21:44:01

好题帮顶一下

penelope0823 · 发表于 2014-3-18 20:18:43

好厉害@!!!

求助一题！！不好意思总打扰大家学习！！

所属分类: GMAT考试

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