Company S produces two kinds of stereos: basic and deluxe. Of the stereos produced by
Company S last month,$$\frac{2}{ 3}$$ were basic and the rest were deluxe. If it takes $$\frac{7}{ 5}$$ 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?
答案：A