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题库 / Prep2007E1-DS-179
A manufacturer conducted a survey to determine how many people buy products P and Q. What fraction of the people surveyed said that they buy neither product P nor product Q ?
(1) ~$\frac{1}{3}$~ of the people surveyed said that they buy product P but not product Q.
(2) ~$\frac{1}{2}$~ of the people surveyed said that they buy product Q.
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.
还没有题目讲解（毕出老师会陆续发布对官方考题的解读，请保持关注）。
(1)中的只买P不买Q意味着不包含两个圆重叠的部分，（2)的买Q，是指的是整个Q的圆。因此1+2刚好是全部圆的部分，用整体的1减去它们就能求得都不买的人的比例。
韦恩图
P 和 Q 不是独立事件 还有 既 P 又 Q 啊~
然而反过头来仔细看题，2）说了买 Q 但没说只买 Q，所以是不是应该理解成包含那部分既买 Q 又买 P 的？
对。
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