GWD7

请大家看看这几题如何解答

Company S produces two kinds of stereos:  basic and deluxe.  Of the stereos produced by Company S last month,  were basic and the rest were deluxe.  If it takes 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?

第一题题干应该少了 2/3were basic and the rest were deluxe. If it takes 7/5as many hours to produce a deluxe stereo as it does to produce a basic stereo

设basic的为b,deluxe的为d,b=2d,生产d的一共(b/2)*7/[(b/2)*7+b*5]=7/17

第二题 5^x*5-5^x=5^3*5^y*124

       124*5^x=5^(3+y)*124

       y=x-3