Q26: 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. 4 B. 6 C. 8 D. 10 E. 12 我的思路:设机器X的速度为a,机器Y的速度为b,得方程式 1)w/a=(w/b)+2 2) 5/4w/(a+b)=3
请问:我列的试子有问题吗?为什么解不出来呢! |