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标题: 有题不会，请指教 [打印本页]

作者: qiqiusa 时间: 2007-12-2 01:09
标题: 有题不会，请指教

A survey of 100 persons revealed that 72 of
them had eaten at restaurant P and that 52 of them had eaten at restaurant Q. Which
of the following could not be the number of persons in the surveyed group who
had eaten at both P and Q?

A. 20 B. 24 C.30 D.50 E.52

正确答案是：A

能帮我解释一下吗？文章最后问题看不明白 “Which
of the following could not be the number of persons in the surveyed group who
had eaten at both P and Q?”

谢谢……

作者: atc 时间: 2007-12-2 02:02

Which of the following could not be the number of persons in the surveyed group who had eaten at both P and Q?”
下面哪个不可能是在P和Q都吃过饭的人数？

其实这到题就是求范围，画图，可得在两家都吃过饭的人数范围[24，52]

作者: qiqiusa 时间: 2007-12-2 11:54
小弟不才，谢谢赐教，嘿嘿

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