Last visit was: 24 Apr 2026, 19:13 It is currently 24 Apr 2026, 19:13
Home
Messages
Tests
Schools
Events
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
avatar
gmattesttaker2
avatar
Joined: 19 May 2014
Last visit: 19 Jul 2016
Posts: 6
Own Kudos:
201
 [61]
Given Kudos: 16
Posts: 6
Kudos: 201
 [61]
A business school event invites all of its graduate and Updated on: 26 Mar 2026, 09:17
Originally posted by gmattesttaker2 on 27 May 2014, 19:01.
Last edited by Bunuel on 26 Mar 2026, 09:17, edited 2 times in total.
3
Kudos
Add Kudos
58
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

65% (hard)

Question Stats:

70% (03:23) correct 30% (03:20) wrong based on 527 sessions

History

Date
Time
Result
Not Attempted Yet
A business school event invites all of its graduate and undergraduate students to attend. Of the students who attend, male graduate students outnumber male undergraduates by a ratio of 7 to 2, and females constitute 70% of the group. If undergraduate students make up 1/6 of the group, which of the following CANNOT represent the number of female graduate students at the event?

A) 18
B) 27
C) 36
D) 72
E) 180

Show Spoiler

I tried to solve using a Double Set Matrix:

------------------Male--------Female---------Total
Graduate 7x 2x 9x
Under Graduate - - (1/6)100
Total 30 70 100

Is it correct here to take the Total as 100 since it is mentioned that females constitute 70% of the group or should the total be an unknown x? Thanks for your help.

Regards,
Sri
ShowHide Answer
Official Answer
B
Most Helpful Reply
User avatar
KarishmaB
User avatar
Joined: 16 Oct 2010
Last visit: 23 Apr 2026
Posts: 16,442
Own Kudos:
79,404
 [16]
Given Kudos: 485
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,442
Kudos: 79,404
 [16]
A business school event invites all of its graduate and 27 May 2014, 22:10
10
Kudos
Add Kudos
6
Bookmarks
Bookmark this Post
gmattesttaker2
Hello,

Can you please assist with this:

A business school event invites all of its graduate and undergraduate students to attend. Of the students who attend, male graduate students outnumber male undergraduates by a ratio of 7 to 2, and females constitute 70% of the group. If undergraduate students make up 1/6 of the group, which of the following CANNOT represent the number of female graduate students at the event?

A) 18
B) 27
C) 36
D) 72
E) 180


OA:
Show Spoiler
B


I tried to solve using a Double Set Matrix:

------------------Male--------Female---------Total
Graduate 7x 2x 9x
Under Graduate - - (1/6)100
Total 30 70 100

Is it correct here to take the Total as 100 since it is mentioned that females constitute 70% of the group or should the total be an unknown x? Thanks for your help.

Regards,
Sri
Show more


Here is how you can use the double set matrix.

...................Male...............Female..............Total
Graduate .......7x..............
UnderGrad......2x......
Total.............9x

Female students make up 70% of the group and so male students make up 30% of the group.
9x = (30/100)*Total
Total = 30x (we got the total number of students in terms of x)

...................Male...............Female..............Total
Graduate .......7x................
UnderGrad......2x......
Total.............9x...................21x.................30x

Undergrad students make 1/6 of the group i.e. (1/6)*30x = 5x

...................Male...............Female..............Total
Graduate .......7x...................18x
UnderGrad......2x...................3x....................5x
Total.............9x...................21x.................30x

So undergrad females must be 3x and grad females must be 18x.

Number of Grad females must be a multiple of 18.
27 is not a multiple of 18 so it cannot be the number of grad females. Answer (B)
General Discussion
User avatar
KarishmaB
User avatar
Joined: 16 Oct 2010
Last visit: 23 Apr 2026
Posts: 16,442
Own Kudos:
79,404
 [1]
Given Kudos: 485
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,442
Kudos: 79,404
 [1]
A business school event invites all of its graduate and 27 May 2014, 22:12
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
gmattesttaker2
Hello,

Can you please assist with this:

A business school event invites all of its graduate and undergraduate students to attend. Of the students who attend, male graduate students outnumber male undergraduates by a ratio of 7 to 2, and females constitute 70% of the group. If undergraduate students make up 1/6 of the group, which of the following CANNOT represent the number of female graduate students at the event?

A) 18
B) 27
C) 36
D) 72
E) 180


OA:
Show Spoiler
B


I tried to solve using a Double Set Matrix:

------------------Male--------Female---------Total
Graduate 7x 2x 9x
Under Graduate - - (1/6)100
Total 30 70 100

Is it correct here to take the Total as 100 since it is mentioned that females constitute 70% of the group or should the total be an unknown x? Thanks for your help.

Regards,
Sri
Show more

If you do assume the total to be 100, you will get fractions at places since the total is 30x. So the total must be a multiple of 30. In such cases, it is best to get everything in a single variable.
avatar
gmattesttaker2
avatar
Joined: 19 May 2014
Last visit: 19 Jul 2016
Posts: 6
Own Kudos:
201
Given Kudos: 16
Posts: 6
Kudos: 201
A business school event invites all of its graduate and 31 May 2014, 20:28
Kudos
Add Kudos
Bookmarks
Bookmark this Post
VeritasPrepKarishma
gmattesttaker2
Hello,

Can you please assist with this:

A business school event invites all of its graduate and undergraduate students to attend. Of the students who attend, male graduate students outnumber male undergraduates by a ratio of 7 to 2, and females constitute 70% of the group. If undergraduate students make up 1/6 of the group, which of the following CANNOT represent the number of female graduate students at the event?

A) 18
B) 27
C) 36
D) 72
E) 180


OA:
Show Spoiler
B


I tried to solve using a Double Set Matrix:

------------------Male--------Female---------Total
Graduate 7x 2x 9x
Under Graduate - - (1/6)100
Total 30 70 100

Is it correct here to take the Total as 100 since it is mentioned that females constitute 70% of the group or should the total be an unknown x? Thanks for your help.

Regards,
Sri


Here is how you can use the double set matrix.

...................Male...............Female..............Total
Graduate .......7x..............
UnderGrad......2x......
Total.............9x

Female students make up 70% of the group and so male students make up 30% of the group.
9x = (30/100)*Total
Total = 30x (we got the total number of students in terms of x)

...................Male...............Female..............Total
Graduate .......7x................
UnderGrad......2x......
Total.............9x...................21x.................30x

Undergrad students make 1/6 of the group i.e. (1/6)*30x = 5x

...................Male...............Female..............Total
Graduate .......7x...................18x
UnderGrad......2x...................3x....................5x
Total.............9x...................21x.................30x

So undergrad females must be 3x and grad females must be 18x.

Number of Grad females must be a multiple of 18.
27 is not a multiple of 18 so it cannot be the number of grad females. Answer (B)
Show more

Hello Karishma,

Thank you very much for the excellent explanation.

Best Regards,
Sri
User avatar
PiyushK
User avatar
Joined: 22 Mar 2013
Last visit: 31 Aug 2025
Posts: 588
Own Kudos:
5,054
 [1]
Given Kudos: 235
Status:Everyone is a leader. Just stop listening to others.
Location: India
GPA: 3.51
WE:Information Technology (Computer Software)
Products:
My Reviews
Posts: 588
Kudos: 5,054
 [1]
A business school event invites all of its graduate and 09 Jun 2014, 09:10
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
A business school event invites all of its graduate and undergraduate students to attend. Of the students who attend, male graduate students outnumber male undergraduates by a ratio of 7 to 2, and females constitute 70% of the group. If undergraduate students make up 1/6 of the group, which of the following CANNOT represent the number of female graduate students at the event?

I solved this question in a different way and stuck:

I considered total students = X

Females 70% of X
Males 30% of X

Male grad to undergrad ratio = 7:2

Therefore male undergrads in X = 2/9 * 3/10 X

= 1/15 * X

1/6 of the group are undergrad, i.e 1/6 * X

Female undergrad = 1/6 * X - 1/15 * X = X/10

Thus, Female grad = (7/10 * X )- X/10 = 3/5 * X

As per my solution Female grad number must be divisible by 3 and all choices are divisible by 3. I am not able to identify any error in my approach.. please help to identify mistake in my solution.
User avatar
KarishmaB
User avatar
Joined: 16 Oct 2010
Last visit: 23 Apr 2026
Posts: 16,442
Own Kudos:
79,404
 [1]
Given Kudos: 485
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,442
Kudos: 79,404
 [1]
A business school event invites all of its graduate and 09 Jun 2014, 21:24
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
PiyushK
A business school event invites all of its graduate and undergraduate students to attend. Of the students who attend, male graduate students outnumber male undergraduates by a ratio of 7 to 2, and females constitute 70% of the group. If undergraduate students make up 1/6 of the group, which of the following CANNOT represent the number of female graduate students at the event?

I solved this question in a different way and stuck:

I considered total students = X

Females 70% of X
Males 30% of X

Male grad to undergrad ratio = 7:2

Therefore male undergrads in X = 2/9 * 3/10 X

= 1/15 * X

1/6 of the group are undergrad, i.e 1/6 * X

Female undergrad = 1/6 * X - 1/15 * X = X/10

Thus, Female grad = (7/10 * X )- X/10 = 3/5 * X

As per my solution Female grad number must be divisible by 3 and all choices are divisible by 3. I am not able to identify any error in my approach.. please help to identify mistake in my solution.
Show more


You get that Number of female grads is (3/5)*X.
Note that X needs to be divisible by 10 since number of female is 7/10*X, number of males is 3/10*X etc.
So X should be a multiple of 2. Since number of female grads is (3/5)*X, number of female grads should be a multiple of 2 too. So 27 is not possible.
avatar
thisisbansalgaurav
avatar
Joined: 08 Jun 2014
Last visit: 04 Jul 2014
Posts: 1
Own Kudos:
3
 [2]
Posts: 1
Kudos: 3
 [2]
A business school event invites all of its graduate and 09 Jun 2014, 22:21
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
I tried it this way.

MG: MUG => 7/9 : 2/9
M:F => 3/10 : 7/10
UG:G => 1/6 : 5/6

If we take LCM of the denominators i.e. 9,10 and 6, we get 90.

Wouldnt this mean that this group HAS TO HAVE the total number of students in multiples of 90.
If so then FG would be 54/90 or 3/5 or 60% of the group to be Female Grads.
Only 27 is the number which is not a multiple of 6, hence thats the correct answer.
User avatar
dina98
User avatar
Joined: 14 Jul 2014
Last visit: 07 Jun 2019
Posts: 121
Own Kudos:
63
Given Kudos: 110
Location: United States
Schools: Duke '20 (D)
GMAT 1: 720 Q50 V37
GMAT 2: 600 Q48 V27
GPA: 3.2
Products:
My Reviews
Schools: Duke '20 (D)
GMAT 2: 600 Q48 V27
Posts: 121
Kudos: 63
A business school event invites all of its graduate and 28 Mar 2016, 14:08
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The ratio of female grad to female undergrad is 6:1. The answer will not be divisble by 6. So, 27-B.
avatar
bethebest
avatar
Joined: 01 Mar 2014
Last visit: 24 Mar 2017
Posts: 94
Own Kudos:
37
Given Kudos: 616
Schools: Tepper '18
Schools: Tepper '18
Posts: 94
Kudos: 37
A business school event invites all of its graduate and 01 Apr 2016, 22:52
Kudos
Add Kudos
Bookmarks
Bookmark this Post
VeritasPrepKarishma
gmattesttaker2
Hello,

Can you please assist with this:

A business school event invites all of its graduate and undergraduate students to attend. Of the students who attend, male graduate students outnumber male undergraduates by a ratio of 7 to 2, and females constitute 70% of the group. If undergraduate students make up 1/6 of the group, which of the following CANNOT represent the number of female graduate students at the event?

A) 18
B) 27
C) 36
D) 72
E) 180


OA:
Show Spoiler
B


I tried to solve using a Double Set Matrix:

------------------Male--------Female---------Total
Graduate 7x 2x 9x
Under Graduate - - (1/6)100
Total 30 70 100

Is it correct here to take the Total as 100 since it is mentioned that females constitute 70% of the group or should the total be an unknown x? Thanks for your help.

Regards,
Sri


Here is how you can use the double set matrix.

...................Male...............Female..............Total
Graduate .......7x..............
UnderGrad......2x......
Total.............9x

Female students make up 70% of the group and so male students make up 30% of the group.
9x = (30/100)*Total
Total = 30x (we got the total number of students in terms of x)

...................Male...............Female..............Total
Graduate .......7x................
UnderGrad......2x......
Total.............9x...................21x.................30x

Undergrad students make 1/6 of the group i.e. (1/6)*30x = 5x

...................Male...............Female..............Total
Graduate .......7x...................18x
UnderGrad......2x...................3x....................5x
Total.............9x...................21x.................30x

So undergrad females must be 3x and grad females must be 18x.

Number of Grad females must be a multiple of 18.
27 is not a multiple of 18 so it cannot be the number of grad females. Answer (B)
Show more

I really like your posts Karishma, superb explanations.
My only concern there are times I don't know how to approach a question, but after reading your explanations it makes perfect sense. How do i work on this?
User avatar
Nikkb
User avatar
Current Student
Joined: 02 Jul 2017
Last visit: 08 Jan 2024
Posts: 226
Own Kudos:
318
 [1]
Given Kudos: 70
Concentration: Entrepreneurship, Technology
Schools: Tepper '20 (M$) McCombs '20 (A) Darden '20 (D) Haas '20 (D) Anderson '20 (D)
GMAT 1: 730 Q50 V38
Schools: Tepper '20 (M$) McCombs '20 (A) Darden '20 (D) Haas '20 (D) Anderson '20 (D)
GMAT 1: 730 Q50 V38
Posts: 226
Kudos: 318
 [1]
A business school event invites all of its graduate and 17 Sep 2017, 00:12
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Given\(\frac{Male Grad}{Male Undergard} =\frac{MG}{MUG}=\frac{7}{2}\)

=> MG = 7x and MUG =2x

No. of females = F = 70 % of total = 0.7T
=> No. of males = M = T - 0.7T = 0.3T

=> No. of Male Grad + No. of Male Undergrad = Total Males => MG+MUG = M => 7x+2x =0.3T => 9x = 0.3T => T = 30x

Total Undergrad = UG = 1/6th of total = \(\frac{T}{6}\) =\(\frac{30x}{6}\) =5x

=> Male undergrad + Female undergrad = Total Undergrad students => MUG + FUG = UG => 2x+FUG = 5x => FUG = 3x

=> Female Undergrad + Female Grad = Total Female students = > FUG + FG = F => 3x+FG = 0.7 T = 0.7*30x => FG = 21x-3x = 18x

So number of FG need to be a multiple of 18. Wrong out option which is not a multiple of 18.

Answer: B
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,975
Own Kudos:
1,117
Posts: 38,975
Kudos: 1,117
A business school event invites all of its graduate and 07 Oct 2025, 14:35
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.
Moderators:
Bunuel
Math Expert
109818 posts
Krunaal
Tuck School Moderator
853 posts