June 25,1982, fell on a Friday. On which day of the week did June 25, 1987, fall? Thursday.
我怎么算的是星期二?
Running at their respective constant rate, machine x takes 2 days longer to produce w weights than machine y. At these rates, if the two machines together produce 5/4 w weights in 3 days, how many days would it take machine x along to produce 2w weights?
12
我列了两个公式: 3x+3y=5/4 1/x+1/y (x y, 分别为其工作效率)这个要怎么算?
谢谢
有人帮忙解释一下吗?
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