I don't understand the question, Yelp !!!

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I don't understand the question, Yelp !!!

by candygal79 » Thu Mar 13, 2014 6:25 am
If a=2/7 b and b=7/3 c then what percent of a is c?

A)50 %
B) 57 1/7 %
C) 66 2/3 %
D) 125%
E)150%

Thanks

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by Brent@GMATPrepNow » Thu Mar 13, 2014 6:30 am
candygal79 wrote:If a = (2/7)b and b = (7/3)c, then what percent of a is c?

A)50 %
B) 57 1/7 %
C) 66 2/3 %
D) 125%
E)150%

Thanks
Given: a = (2/7)b and b = (7/3)c

Take a = (2/7)b and replace b with (7/3)c to get: a = (2/7)(7/3)c
Simplify: a = (2/3)c
So, a is 2/3 of c
Or we can say that c is 3/2 of a.
In other words, c is [spoiler]150%[/spoiler] of a

Answer: E

Cheers,
Brent
Last edited by Brent@GMATPrepNow on Thu Mar 13, 2014 7:09 am, edited 2 times in total.
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by GMATGuruNY » Thu Mar 13, 2014 7:00 am
candygal79 wrote:If a=2/7 b and b=7/3 c then what percent of a is c?

A)50 %
B) 57 1/7 %
C) 66 2/3 %
D) 125%
E)150%

Thanks
Let c = 3.
Then:
b = (7/3)c = (7/3)(3) = 7.
a = (2/7)b = (2/7)(7) = 2.

Since a=2 and c=3, the question stem becomes:
What percent of 2 is 3?

Translate the resulting question into math, word by word.
The words in the question stem translate as follows:
what percent --> x/100.
of --> MULTIPLY.
is --> =.
Translating the resulting question into math, we get:
(x/100) * a = c
(x/100) * 2 = 3
2x = 300
x = 150.

The correct answer is E.
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by candygal79 » Thu Mar 13, 2014 7:05 am
Thank you Sirs. NOW i clearly understood both the explanation.

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by Abhishek009 » Fri Mar 14, 2014 8:57 am
candygal79 wrote:If a=2/7 b and b=7/3 c then what percent of a is c?
Let c = 21

b = 49

a = 14
candygal79 wrote:What percent of a is c?
c/a * 100%

=> ( 21/14 )*100%

=> 3/2*100%

=> 150%
Abhishek