Gmat prep, students problem

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Gmat prep, students problem

by LFalken » Mon Sep 07, 2009 9:29 am
Hello, If someone could shed some light on this problem that would be great. Thanks


In a certain senior class, 72 percent of the male students and 80 percent of the female students have applied to college. What fraction of the students in the senior class are male?

(1) there are 840 students in the senior class.

(2) 75 percent of the students in the senior class have applied to college.


Answer is B, and I do not follow....
LFAL

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by abhishekkishore12 » Mon Sep 07, 2009 10:55 am
Male students in the senior class = M
Female students in the senior class = F
Therefore,total students= M+F
Number of male students who applied for college = (72/100)M
Number of female students who applied for college = (80/100)F

Therefore total students who applied for college = (72/100)M + (80/100)F

From (2) it is given that a total of 75% students apllied for college i.e. (75/100)(M+F)

Therefore (75/100)(M+F) = (72/100)M + (80/100)F

Solve the above equation to get 5F = 3M
Therefore the ration of male students to the total no of students = M/(M+F)
i.e M/(M+(3M/5)) WHICH GIVES THE RATIO AS 5/8