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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?
A.\x054
B.\x056
C.\x058
D.\x0510
E.\x0512
人气:116 ℃ 时间:2020-05-09 09:17:48
解答
设x用了x天做w个 y用了x-2天 则x一天做w\x,y一天w\(x-2)
3天x,y一起做了
3(w\x+w\(x-2))=5\4w
解方程 约掉w
12\x+12\(x-2)=5
化为整式方程得到(5x-4)(x-6)=0
x1=0.8 x2=6
检验两个都符合原方程但是x1不符合实际
所以x为6
所以x做2w用12天 选e
求采纳爪机打字不容易
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