一件工程，甲单独做要6小时，乙单独做要10小时，如果按甲、乙、甲、乙…顺序交替工作，每次1小时，那么需要小时完成．_刷题宝

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一件工程，甲单独做要6小时，乙单独做要10小时，如果按甲、乙、甲、乙…顺序交替工作，每次1小时，那么需要（　　）小时完成．

A：7

B：7 $\frac{1}{2}$

C：7 $\frac{1}{3}$

D：7 $\frac{1}{4}$

上一题下一题 0.0难度选择题更新时间:2016-02-19 03:13:47

答案(点此获取答案解析）

C

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