[求助]GWD-1-26 涛涛

双鱼游

在Manhattan论坛找到的，算起来更简单一点，它是假设x机器完成w件的时间是T

Let T total number of days taken by machine X to produce W widgets.Then Work done by x is 1 day is W/TWork done by machine y in 1 day = W/(T - 2).
Combined work done in 3 days = 3( W/T + W/(t-2) )= 3W( 2T-1 ) / (T- 2) which is equal to 5W/4So equating the two equations we get12( 2T - 1 ) = 5T( T - 2)24T - 12 = 5T2 - 10T5T2 - 32T + 12 = 0(T-6) (5T+2) = 0.
Which gives T = 6.So no. of days to produce 2W widgets = 2T = 12.Ans: E