Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machine Y. At these rates, if the two machines together produce 5/4 w widgets in 3 days, how many days would it take machine X alone to produce 2w widgets?
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设machine x和y的生产速度分别为x、y个widget/day,
根据题干有
w/x-w/y=2
3x+3y=5/4w
求2w/x
令m=w/x,n=w/y
转化为
m-n=2
3/m+3/n=5/4
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