作者northarc (northarc)
看板GMAT
标题[计量] OG 12th p.23 Q24
时间Thu Oct 15 13:39:45 2009
大概是太久没有算数学了，
思考上有点卡住的感觉，
一直想不出来该怎麽算
24.Aaron will jog from home at x miles per hour and then walk back home by
the same route at y miles per hour.
How many miles from home can Aaron jog so that he spends a total of t hours
jogging and walking?
A) (xt)/y
B) (x+t)/(xy)
C) (xyt)/(x+y)
D) (x+y+t)/xy
E) (y+t)/x - t/y
正确答案是C
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※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 219.80.138.130
1F：→ cutefox0108:t*1/(1/X+1/y) 10/15 14:59
2F：→ clplayer:设可以跑m miles,则 x/m + y/m = t,移项後m= t(xy)/(x+y) 10/15 17:07
3F：→ clplayer:订正一下 m/x + m/y = t 10/15 17:07