Data Sufficiency question

by **GMAT Taker** Sun Aug 24, 2008 7:12 pm

In a certain senior class, 72% of the male students and 80% 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% of the students in the senior class have appliked to college

A
B
C
D
E

Correct answer is B. Please explain. Thanks!

by **esledge** Sat Sep 27, 2008 4:24 pm

Is this a GMAT Prep question? Please verify the source, and provide the answer choices. Also, please give us something to go on...where are you stuck? Thank you.

by **Kunal** Sat Sep 27, 2008 5:33 pm

Took lil longer to figure out the answer but here it is.m

let there be x male students and y female students in the class. so the strength of the class is x + y.
our aim is to find out the ratio x/(x+y)

so 0.72x + 0.8y students applied colleges.

1. Is insuffient to find out the ratio mentioned above.

2. tells us that 0.72x + 0.8y = 0.75(x+y)

solving the above equation we get x/y = 5/3
from this we can caluculate the ratio x/(x+y) = 5/8.
So the answer is B.

by **RonPurewal** Tue Oct 14, 2008 4:51 am

if you know the facts about weighted averages that are presented in this post, then you can realize right away that statement 2 is sufficient. you have both "endpoints" as well as the weighted average, so the fraction/weight of each "endpoint" is automatically determined. (you won't have absolute numbers of males and females without statement 1, but you don't care about absolute numbers - just relative numbers.)