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GMAT Prep: Ratio

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GMAT Prep: Ratio

by Skywalker » Sat Oct 02, 2010 10:51 pm
In a certain senior class 72 % male and 80% female have applied to college. What fraction of students in the senior class are male ?

1) There are 840 students in the senior class
2) 75% of the students in senior class have applied to college

[spoiler]OA = B[/spoiler]

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Please help me understand this sum ~
StAy HuNgry sTay fOOlisH
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Source: — Data Sufficiency |
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by ashokkadam » Sat Oct 02, 2010 11:30 pm
From statement 1: we do not know how many number of male students are in the senior class. so INSUFFICIENT.
From statement 2: let's say...
x: total strength
m: total males
f: total females
=> x = m+ f ------Equation (1)

and from statement 2,

0.75x = 0.72m + 0.8f ------Equation (2)

Solving both equations together, we get

0.8x - 0.75x = 0.8m - 0.72m
0.05x = 0.08m
5x=8m
m=5/8x ........SUFFICIENT!!

So, B is the answer

Skywalker wrote:In a certain senior class 72 % male and 80% female have applied to college. What fraction of students in the senior class are male ?

1) There are 840 students in the senior class
2) 75% of the students in senior class have applied to college

[spoiler]OA = B[/spoiler]

----------------------------------------------------------
Please help me understand this sum ~
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by gmatmachoman » Sat Oct 02, 2010 11:32 pm
https://www.beatthegmat.com/ratio-problem-t58531.html

I tried to explain it there!!
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