帮忙解决一道题，英语高手进，谢谢

Two pumps will pump the oil from the tank in 3,75 hours . First pump would pump the oil 4 hours earlier than the second one . How much time does it take to pump the tank with each pump separately?

A. First pump in 6 hours, second one in 10 hours

B. First pump in 7,5 hours, second one in 11,5 hours

C. First pump in 6,5 hours, second one in 10,5 hours

D. First pump in 5 hours, second one in 9 hours

题不会啊

帮忙列出式子 并表明各个未知数代表的含义 选出答案

两台泵一起从油罐里往外抽油，抽完需要3.75小时，分着抽第一台比第二台快4小时。每一台泵单独往外抽油需要多长时间？

先感谢下楼上同学的翻译。

设第一台单独要X小时，第2太要Y小时

得方程组Y-X=4 ; 1/[(1/x)+(1/Y)]=3.75

解得X=4,Y=10

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