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?
4
6
8
10
12
X和Y的产能差2天,而XY3天一共完成了超过1W的,那么Y单独生产肯定在6天以内,因为Y的产能比X大,2个Y肯定比1个X和1个Y要快。假设Y是5天,那么X是7天,没有这个答案,Y 是4天,X是6天,选E。代入也符合。
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