problem solving求解

KatherineWoo · 发表于 2012-1-8 11:10:13

问题：During a trip, Francine traveled X percent of the total distance at an average speed of 40 miles per hour and the rest of the distance at an average speed of 60 miles per hour. In terms of x, what was Francine's average spped of the entire trip?
A 180-x/2
B x+60/4
C 300-x/5
D 600/115-x
E 12000/x+200

疑问：为什么答案要把整个distance假设为100miles才能得出最终正确答案？如果不假设成为100，得出的答案就会不一样，求解啊，谢谢。

sdcar2010 · 发表于 2012-1-8 12:04:35

Are you sure???

linchaoyi · 发表于 2012-1-8 12:28:35

选e吧
因为X percent 所以X要除以100才能化成百分比，然后再算总就行了，不然的话X就是会好大的。。。

GTpower · 发表于 2012-1-8 12:46:02

X pencentage =x%
S/[x%s/40+(1-x%)s/60]
100/[3x/120+(200-x)/120]
100*120/(200+x)

xuchaodream · 发表于 2012-1-8 13:31:33

我靠这题太刁钻了 percent居然要转换??

KatherineWoo · 发表于 2012-1-8 13:56:55

明白了，多谢各位

problem solving求解

所属分类: GMAT考试

正在浏览此版块的会员 ()

浏览过的版块