作者clearfuture (really?)
看板GMAT
标题[计量] PP1-DS-41
时间Thu Nov 19 20:39:29 2009
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.
(解)
设work=1, machineX=Xhour, machineY=Yhour, 问y-x=?
(1) 1/X + 1/Y = 2/3 ^ 1/X
(2) 1/Y = 2^ 1/X
答案是E
可是直觉上两个变数，配上两条式子，为什麽不是C ?tt.cc)
◆ From: 60.245.105.187
1F：推 pei33ho:太神了 正要发问这题 以为自己眼花怎麽PO好了! 想要顺便问 11/19 21:16
2F：→ pei33ho:第二个算式表达对吗? 感觉是1/X=2*1/Y ? 谁能回答一下~谢 11/19 21:18
3F：→ pei33ho:原PO符号写错 次方符号应该是乘号吧!!! 11/19 21:20
4F：→ clearfuture:歹势....第一次PO.....SORRY 11/20 10:43