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麻烦大侠们能解释一下这道弱智的DS的过程吗?
41.
Machines X and Y work at their respective constant rates.How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?
(1) Machines X and Y, working together, fill a production order of this size in two-thirds the time that machine X, working alone, does.
(2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does.
我是设他们效率为X,Y,则
1/x+y = 2/3x , 1/y = 2/x
然后解方程吗?发现X=y,之后呢? |
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