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题库 / Prep2007E2-DS-185
Of the 200 members of a certain association, each member who speaks German also speaks English, and 70 of the members speak only Spanish. If no member speaks all three languages, how many of the members speak two of the three languages?
(1) 60 of the members speak only English.
(2) 20 of the members do not speak any of the three languages.
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.
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each member who speaks German also speaks English 讲德语的人一定讲英语 讲英语的人不一定讲德语
列方程：n+e+g+d+s=200,其中e=只说英语=英语-德语，n=一种都不会，s=只说西语，d=both(英语和西语)。s=70, 求d+s？
(1)e=60
(2)n=20
both
韦恩图：
说G的都说E，所以G是E里面的一个小饼饼。S则可以和E交叉，但不能和G交叉，因为没有人能说3种语言。
how many of the members speak two of the three languages?
会说G的人也会说E！！！
所以！how many of the members speak two of the three languages
是求G+onlyE∩S的人数啊啊啊啊啊！！！
数学问什么一定要看清....
因为没有EGS，所以S+E+G+None+SE+EG+SG=200, 又G全部在E里，所以如果存在SG，就存在SEG，所以不存在SG。
！！题目描述的是： each member who speaks German also speaks English 说G的一定说E，但是说E的不一定要会说G