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标题: 求PREP-DS-2-12解 [打印本页]

作者: jesuisdesole 时间: 2008-8-13 22:32
标题: 求PREP-DS-2-12解

12. 781-!-item-!-187;#058&000341

Sets A, B, and C have some elements in common. If 16 elements are in both A and B, 17 elements are in both A and C, and 18 elements are in both B and C, how many elements do all three of the sets A, B, and C have in common?

(1) Of the 16 elements that are in both A and B, 9 elements are also in C.

(2) A has 25 elements, B has 30 elements, and C has 35 elements.

答案B

谢谢

作者: rearn 时间: 2008-8-14 00:27

翻查过答案，是A：）

作者: 1117520yao 时间: 2008-8-14 04:31
解释一下？没看明白

作者: jesuisdesole 时间: 2008-8-16 20:30

SORRY,答案是A我写成B了

能否给讲解一下怎么得出的A呢?

作者: jesuisdesole 时间: 2008-8-17 22:38

再问~

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