一道数学机经题...集合~求解答

oberon_cn

The table gives three factors to be considered when choosing an Internet service provider and the percent of the 1,200 respondents to a survey who cited that factor as important.  If 30 percent of the respondents cited both “user-friendly” and “fast response time,” what is the maximum possible number of respondents who cited “bargain prices,” but neither “user-friendly” nor “fast response time?”

Factor	Percent of Respondents
User-friendly	56%
Fast response time	48%
Bargain prices	42%

求解答...这个题我看了最新版本的机经，觉得解答有误，希望能有人给个详尽解答

谢谢~

vancechen

user-friendly  :1200*56%=672

fast response time : 1200*48%=576

bargain prices : 1200*  1200*42% =504

both ¨user-friendly〃 and ¨fast response time〃 : 1200*30% =360

672 + 572  -360 =888

1200-888 = 312

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[此贴子已经被作者于2009/9/10 16:23:06编辑过]

oberon_cn

我算出来的也是这个值，可是貌似没有什么变量，也就无所谓题中所说的最大不最大的问题了...