Company S produces two kinds of stereos:basic and deluxe. Of the stereos produced by Company S last month, \frac2 3 were basic and the rest were deluxe. If it takes \frac7 5 as many hours to produce a deluxe stereo as it does to produce a basic stereo, then the number of hours it took to produce the deluxe stereos last month was what fraction of the total number of hours it took to produce all the stereos?
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A\frac{7}{17}
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B\frac{14}{31}
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C\frac{7}{15}
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D\frac{17}{35}
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E\frac{1}{2}
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正确答案: A