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【OG20-P179-217题】
For the past n days, the average (arithmetic mean) daily production at a company was 50 units. If today’s production of 90 units raises the average to 55 units per day, what is the value of n ?
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分析B选项
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分析E选项
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答案 E
【解析】
根据题意有
，从而解得n=7。
【知识补充】
平均数，是表示一组数据集中趋势的量数，是指在一组数据中所有数据之和再除以这组数据的个数。它是反映数据集中趋势的一项指标。求平均数关键在于确定“总数量”以及和总数量对应的“总份数”。
256671qosj
简便算法：（90-55）/（55-50）=7
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2021-02-16 22:51:07
256671qosj
简便算法：（90-55）/（55-50）=7
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2021-02-16 22:50:19
331637w
求助，为什么是n+1
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2020-11-14 18:45:27
331637w回复331637w
因为是today？ 就比past day多一天？
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2020-11-14 18:51:22
张晓婧
(50n+90)/(n+1)=55 n是past days
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2018-08-01 22:34:45
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题目信息1m26s
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84%
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