Find all School-related info fast with the new School-Specific MBA Forum

It is currently 27 Aug 2014, 17:33

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

In a certain senior class, 75 percent of the male students

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
avatar
Joined: 22 Jun 2005
Posts: 364
Location: London
Followers: 1

Kudos [?]: 4 [0], given: 0

GMAT Tests User
In a certain senior class, 75 percent of the male students [#permalink] New post 08 Apr 2006, 08:50
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 1 sessions
In a certain senior class, 75 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
Manager
Manager
avatar
Joined: 25 Mar 2006
Posts: 132
Location: Stonybrook Univ
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 08 Apr 2006, 10:00
statement 1 ... nothing much here

statement 2 gives us .75x(where x is the number of males)+.80y(where y is the number of females)=.75 z( z is x+y or total number of students )

.75x+.80y=.75z we can write y as y=z-x then we get

.75x+.80z-.80x=.75z ... we need to solve for (x/z) and this could be done

but this only gives us the fraction of the males which applied to college ... we still dont know about the ones that didnt..

am i missing something ?
Manager
Manager
User avatar
Joined: 09 Feb 2006
Posts: 129
Location: New York, NY
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 08 Apr 2006, 12:50
I just got this same question in GMATPrep. I put E. We need to know the percentage of students that are male to answer this question (at least that's what I thought), but we don't. The OA is B, but that made no sense to me.
Senior Manager
Senior Manager
avatar
Joined: 22 Nov 2005
Posts: 482
Followers: 1

Kudos [?]: 3 [0], given: 0

GMAT Tests User
 [#permalink] New post 08 Apr 2006, 13:13
jcgoodchild wrote:
I just got this same question in GMATPrep. I put E. We need to know the percentage of students that are male to answer this question (at least that's what I thought), but we don't. The OA is B, but that made no sense to me.


jcgoodchild,

trick here is its asking ratio of number male students to total number of students. So we don't need A because we can replace female students by total students - Male students.

Hope this will help.
Manager
Manager
avatar
Joined: 25 Mar 2006
Posts: 132
Location: Stonybrook Univ
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 08 Apr 2006, 13:34
gmat_crack can you please solve this question fully.
Manager
Manager
User avatar
Joined: 09 Feb 2006
Posts: 129
Location: New York, NY
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 08 Apr 2006, 17:08
GMAT_Crack -- I realized what the question is asking. I had written out a whole post explaining the issue when I think I stumbled on the answer.

Ok, so we want to find the percentage of students who are male. We know a couple of things. 72% of males applied to college and 80% of females applied to college, and from B we know that this is equal to 75% of the student body.

(.72m + .8f) / (m+f) = .75

To your point, they want the ratio of male to femal students.

.72m + .8f = .75m + .75f
.05f = .03m

m/f = .05/.03 = 5/3

So the fraction of male students is 5/8 ths. Sound right?
VP
VP
avatar
Joined: 28 Mar 2006
Posts: 1390
Followers: 2

Kudos [?]: 18 [0], given: 0

GMAT Tests User
 [#permalink] New post 08 Apr 2006, 17:15
m+f = t (total) ----(i)

.75m + .8f = .75t ----(ii)

Divide (i) by z

m/t + f/t = 1 ------(iii)

divide (ii) also by "t" you get the value of f/t = 1- m/t

So B is enough 'cos you are asked for the portion of the males in the total class but not the # os males....
Manager
Manager
avatar
Joined: 21 Dec 2005
Posts: 105
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 08 Apr 2006, 17:22
jcgoodchild wrote:
GMAT_Crack -- I realized what the question is asking. I had written out a whole post explaining the issue when I think I stumbled on the answer.

Ok, so we want to find the percentage of students who are male. We know a couple of things. 72% of males applied to college and 80% of females applied to college, and from B we know that this is equal to 75% of the student body.

(.72m + .8f) / (m+f) = .75

To your point, they want the ratio of male to femal students.

.72m + .8f = .75m + .75f
.05f = .03m

m/f = .05/.03 = 5/3

So the fraction of male students is 5/8 ths. Sound right?


If you use .75 as given in the question instead of .72 you won't get a ratio!!
SVP
SVP
avatar
Joined: 14 Dec 2004
Posts: 1711
Followers: 1

Kudos [?]: 32 [0], given: 0

GMAT Tests User
 [#permalink] New post 08 Apr 2006, 20:13
IMO, what we need is % of male students in the senior class. (fraction)

Let's assume there are 100 students in senior class.
Then,
0.75x + 0.8(100-x) = 0.75

We can solve for "x", which in itself is a fraction (or percent), So "B".
Senior Manager
Senior Manager
avatar
Joined: 22 Nov 2005
Posts: 482
Followers: 1

Kudos [?]: 3 [0], given: 0

GMAT Tests User
 [#permalink] New post 08 Apr 2006, 20:30
jcgoodchild wrote:
GMAT_Crack -- I realized what the question is asking. I had written out a whole post explaining the issue when I think I stumbled on the answer.

Ok, so we want to find the percentage of students who are male. We know a couple of things. 72% of males applied to college and 80% of females applied to college, and from B we know that this is equal to 75% of the student body.

(.72m + .8f) / (m+f) = .75

To your point, they want the ratio of male to femal students.

.72m + .8f = .75m + .75f
.05f = .03m

m/f = .05/.03 = 5/3

So the fraction of male students is 5/8 ths. Sound right?


Hey dude,
You are calculating the ratio of m/f, but we need here m/T where T is the total number of students.
so T = m + f
--> f = T-m
Now in equation in blue, replace f = t-m


------> [ .72m + .8(T-m)] / T = .75

from this we need to get m/T.

---------> .8 - .08*m/T = .75

---------> .05 = .08*m/T
---> m/T = 5/8

Hope this will help everyone.
Manager
Manager
avatar
Joined: 21 Dec 2005
Posts: 105
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 08 Apr 2006, 21:06
vivek123 wrote:
IMO, what we need is % of male students in the senior class. (fraction)

Let's assume there are 100 students in senior class.
Then,
0.75x + 0.8(100-x) = 0.75

We can solve for "x", which in itself is a fraction (or percent), So "B".


If you solve for x you get a value that is greater than 100 students which is not correct.
Manager
Manager
avatar
Joined: 21 Dec 2005
Posts: 105
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 08 Apr 2006, 21:07
gmat_crack wrote:
jcgoodchild wrote:
GMAT_Crack -- I realized what the question is asking. I had written out a whole post explaining the issue when I think I stumbled on the answer.

Ok, so we want to find the percentage of students who are male. We know a couple of things. 72% of males applied to college and 80% of females applied to college, and from B we know that this is equal to 75% of the student body.

(.72m + .8f) / (m+f) = .75

To your point, they want the ratio of male to femal students.

.72m + .8f = .75m + .75f
.05f = .03m

m/f = .05/.03 = 5/3

So the fraction of male students is 5/8 ths. Sound right?


Hey dude,
You are calculating the ratio of m/f, but we need here m/T where T is the total number of students.
so T = m + f
--> f = T-m
Now in equation in blue, replace f = t-m


------> [ .72m + .8(T-m)] / T = .75

from this we need to get m/T.

---------> .8 - .08*m/T = .75

---------> .05 = .08*m/T
---> m/T = 5/8

Hope this will help everyone.


It is not .72 it is .75 and you cannot deduce the fraction if you follow that equation

Last edited by jodeci on 08 Apr 2006, 21:16, edited 1 time in total.
SVP
SVP
avatar
Joined: 14 Dec 2004
Posts: 1711
Followers: 1

Kudos [?]: 32 [0], given: 0

GMAT Tests User
 [#permalink] New post 08 Apr 2006, 21:08
jodeci wrote:
vivek123 wrote:
IMO, what we need is % of male students in the senior class. (fraction)

Let's assume there are 100 students in senior class.
Then,
0.75x + 0.8(100-x) = 75

We can solve for "x", which in itself is a fraction (or percent), So "B".


If you solve for x you get a value that is greater than 100 students which is not correct.


oops, i made a mistake....corrected in red.
Manager
Manager
avatar
Joined: 21 Dec 2005
Posts: 105
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 08 Apr 2006, 21:19
vivek123 wrote:
jodeci wrote:
vivek123 wrote:
IMO, what we need is % of male students in the senior class. (fraction)

Let's assume there are 100 students in senior class.
Then,
0.75x + 0.8(100-x) = 75

We can solve for "x", which in itself is a fraction (or percent), So "B".


If you solve for x you get a value that is greater than 100 students which is not correct.


oops, i made a mistake....corrected in red.


Still not right, you get 100 for x which is the same as the number you chose for all students meaning female students are zero.
Senior Manager
Senior Manager
avatar
Joined: 05 Jan 2006
Posts: 383
Followers: 1

Kudos [?]: 16 [0], given: 0

GMAT Tests User
 [#permalink] New post 09 Apr 2006, 07:54
trivikram wrote:
m+f = t (total) ----(i)

.75m + .8f = .75t ----(ii)

Divide (i) by z

m/t + f/t = 1 ------(iii)

divide (ii) also by "t" you get the value of f/t = 1- m/t

So B is enough 'cos you are asked for the portion of the males in the total class but not the # os males....


Agree with analysis B is enough, though I ended up selecting E at first glance...
Intern
Intern
avatar
Joined: 01 Feb 2006
Posts: 36
Followers: 0

Kudos [?]: 3 [0], given: 0

 [#permalink] New post 09 Apr 2006, 08:44
I keep getting m/t = 1, which makes little sense to me. It seems that everyone is getting this ratio too. Perhaps this is truly the answer. I've been scouring my calculation for mistakes but everything I have down is logical. I don't think there are any females in this school....

I've tried it through formulas and charts. Everything points to 0 females and all males. Hell, you can even use the 1st statement they give you and try it out with that. It'll give you 840 males.

Good luck...
VP
VP
User avatar
Joined: 29 Dec 2005
Posts: 1351
Followers: 6

Kudos [?]: 28 [0], given: 0

GMAT Tests User
Re: DS:College [#permalink] New post 09 Apr 2006, 13:04
macca wrote:
In a certain senior class, 75 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


the question seems poorly structured for me because if there are male and female, both, students in the college, 75 percent of the male students and 80 percent of the female comprise more than 75% of total.

but if 75 percent of the male students and 80 percent of the female comprise more than 75% of total, then thre are only male students. so the fraction of male student is 1 (or 100%).

lets suppose total = 100
male = x
0.75x + 0.8(100-x) = 75
0.75x + 80 -0.8x = 75
0.75x -0.8x = 75-80
0.05x = 5
x = 100

if so, B is enough...
Senior Manager
Senior Manager
avatar
Joined: 08 Sep 2004
Posts: 258
Location: New York City, USA
Followers: 1

Kudos [?]: 9 [0], given: 0

GMAT Tests User
 [#permalink] New post 10 Apr 2006, 07:45
Here is my take on this -

using the same convention, x - male, y - female, T - total

Condition1 : Doesn't give us anything.

Condition2 :
0.75 x + 0.80y = 0.75T - where T = x + y
=> 0.75x + (0.75 + 0.05) y = 0.75T
=> 0.75(x+y) + 0.05y = 0.75T
=> 0.75T + 0.05y = 0.75T

=> y = 0, i.e. there are no females in the class. So what fraction of the students are male, 100%.

Hence B.
Senior Manager
Senior Manager
avatar
Joined: 22 Jun 2005
Posts: 364
Location: London
Followers: 1

Kudos [?]: 4 [0], given: 0

GMAT Tests User
 [#permalink] New post 11 Apr 2006, 00:50
yeah, but it's from gmatprep!!
Manager
Manager
avatar
Joined: 25 Mar 2006
Posts: 132
Location: Stonybrook Univ
Followers: 1

Kudos [?]: 1 [0], given: 0

 [#permalink] New post 11 Apr 2006, 03:22
hehe this problem sucks :) the only reason i would think C is because i kept getting 0 females ... oh well hope i dont get something this silly on my test
  [#permalink] 11 Apr 2006, 03:22
    Similar topics Author Replies Last post
Similar
Topics:
In a certain senior class 72 percent of the male students vmalaiya 2 02 Jan 2007, 12:50
In a certain senior class, 72 percent of the male students lfox2 3 26 Nov 2006, 06:09
In a certain senior class, 72 percent of the male students Matador 3 15 Apr 2006, 13:35
In a certain senior class, 72 percent of the male students joemama142000 4 18 Dec 2005, 12:28
In a certain senior class, 72 percent of the male students Darth_McDaddy 3 02 Oct 2005, 09:44
Display posts from previous: Sort by

In a certain senior class, 75 percent of the male students

  Question banks Downloads My Bookmarks Reviews Important topics  

Go to page    1   2    Next  [ 21 posts ] 



GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.