241.One project ,A needs 12hours to finish it alone,while B needs 15hours to finish it alone.After A and B working together for an hour ,then A works an hour,B works an hour.A and B turn down like this .So how many hours does the project need?
问题描述：
241.One project ,A needs 12hours to finish it alone,while B needs 15hours to finish it alone.After A and B working together for an hour ,then A works an hour,B works an hour.A and B turn down like this .So how many hours does the project need?
答
不是一个整数，答案是11.2小时。
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答
小学的题.翻译如下:一项工程,A独自完成需要12小时,B独自完成需要15小时.A和B共同工作1小时后,A独自工作一小时,然后B独自工作一小时这样轮流下去,完成这项工程需要多少个小时?A的工作效率是1/12,B的工作效率是1/15,也...