鼠穴两题，算不出答案，求助！

serenashu · 发表于 2010-10-16 12:45:58

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

答案是E，算不出来~~

Q17:

In Town X, 64 percent of the population are employed, and 48 percent of the population are employed males.What percent of the employed people in Town X are females?

A.16%

B.25%

C.32%

D.40%

E.52%

答案是B，为什么？

BlackTTea · 发表于 2010-10-16 13:00:51

第一题，设生产w widgtes X需要的时间为x，则Y需要（x-2）。列方程w/x+w/(x-2)=(5/4w)/3,解出x=6（还有一个解舍去，因为x-2>0）。X生产2w就是需要2*6=12小时

BlackTTea · 发表于 2010-10-16 13:01:52

第二题~用（64%-48%）/64%=25%

BlackTTea · 发表于 2010-10-16 13:02:50

因为问的是employed female占employed的比例~

jizizhuanjia · 发表于 2010-10-16 13:09:39

1. w/x-w/y=2
5/4w=3(x+y)
求：n, n=2w/x
将w/x-w/y=2；5/4w=3(x+y)两式整合去y得出w/x=2+12w/(5w-12x)
化简得出：5w*w-34wx+24x*x=0
求得w/x=6, n=2w/x=12

鼠穴两题，算不出答案，求助！

所属分类: GMAT考试

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