BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Sets

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Legendary Member
Posts: 588
Joined: Sun Oct 16, 2011 9:42 amFollowed by: 9 members
Location: New Delhi, India
Thanked: 130 times
GMAT Score:720
by rijul007 » Thu Feb 16, 2012 3:14 am
Image

The table above shows the result of survey of 100 students who responded with "For" or "Against" or "Not sure" when asked about the Debate choice of the Topic A and Topic B.


What was the number of students who responded "For" for both Topics?

(1) The number of students who did not respond "For" for either Topic was 40.

(2) The number of students who responded "Against" for both Topics was 20.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members
Location: New York, NY
Thanked: 13060 times
GMAT Score:790

by GMATGuruNY » Thu Feb 16, 2012 7:23 am
rijul007 wrote:Image

The table above shows the result of survey of 100 students who responded with "For" or "Against" or "Not sure" when asked about the Debate choice of the Topic A and Topic B.


What was the number of students who responded "For" for both Topics?


(1) The number of students who did not respond "For" for either Topic was 40.

(2) The number of students who responded "Against" for both Topics was 20.

Total "For" voters = total for A + total for B - total for both.

The big idea with overlapping groups is to SUBTRACT THE OVERLAP. In the problem above, there is an overlap between those who voted for A and those who voted for B. When we count the total voters for A and the total voters for B, the OVERLAP -- the students who voted "for" in regards to both topics -- gets counted twice. So we need to SUBTRACT these students so that they are not double-counted.

Since total for A = 30 and total for B = 40:
Total "For" = 30+40 - both
Both = 70 - total "For".

Question rephrased: What was the total number of "For" voters?

Statement 1: The number of students who did not respond "For" for either topic was 40.
Since there were 100 voters, and 40 did NOT respond "For", the total number who DID respond "For" -- in other words, the total number of "For" voters -- was 60.
SUFFICIENT.

Statement 2: The number of students who responded "Against" for both Topics was 20.
No way to determine the total number of "For" voters.
INSUFFICIENT.

The correct answer is A.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 934
Joined: Tue Nov 09, 2010 5:16 amFollowed by: 14 members
Location: AAMCHI MUMBAI LOCAL
Thanked: 63 times

by [email protected] » Fri Feb 17, 2012 4:47 am
The table above shows the result of survey of 100 students who responded with "For" or "Against" or "Not sure" when asked about the Debate choice of the Topic A and Topic B.


What was the number of students who responded "For" for both Topics?

(1) The number of students who did not respond "For" for either Topic was 40.

(2) The number of students who responded "Against" for both Topics was 20.



Overall 1min and 46 secs taken to answer this question, and also got it right...

COrrect explanation given by Mitch!!!
IT IS TIME TO BEAT THE GMAT

LEARNING, APPLICATION AND TIMING IS THE FACT OF GMAT AND LIFE AS WELL... KEEP PLAYING!!!

Whenever you feel that my post really helped you to learn something new, please press on the 'THANK' button.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 268
Joined: Mon Mar 15, 2010 12:10 am
Thanked: 13 times

by shekhar.kataria » Fri Feb 17, 2012 4:58 am
Good Question. This is same as an OG Question in OG 12.
Restlessness and discontent are the first necessities of progress.--Thomas A. Edison

If you find this post helpful, let me know by clicking thanks above :-)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 242
Joined: Fri Aug 01, 2008 8:49 am
Location: Delhi
Thanked: 6 times

by ranjeet75 » Sat Feb 18, 2012 5:53 am
[quote="GMATGuruNY"][quote="rijul007"][img]https://s3.amazonaws.com/production.gro ... 5696/4.jpg[/img]

The table above shows the result of survey of 100 students who responded with "For" or "Against" or "Not sure" when asked about the Debate choice of the Topic A and Topic B.


What was the number of students who responded "For" for both Topics?


(1) The number of students who did not respond "For" for either Topic was 40.

(2) The number of students who responded "Against" for both Topics was 20.[/quote]


[b]Total "For" voters = total for A + total for B - total for both.[/b]

The big idea with overlapping groups is to SUBTRACT THE OVERLAP. In the problem above, there is an overlap between those who voted for A and those who voted for B. When we count the total voters for A and the total voters for B, the OVERLAP -- the students who voted "for" in regards to both topics -- gets counted twice. So we need to SUBTRACT these students so that they are not double-counted.

Since total for A = 30 and total for B = 40:
Total "For" = 30+40 - both
Both = 70 - total "For".

Question rephrased: What was the total number of "For" voters?

[b]Statement 1: The number of students who did not respond "For" for either topic was 40.[/b]
Since there were 100 voters, and 40 did NOT respond "For", the total number who DID respond "For" -- in other words, the total number of "For" voters -- was 60.
SUFFICIENT.

[b]Statement 2: The number of students who responded "Against" for both Topics was 20.[/b]
No way to determine the total number of "For" voters.
INSUFFICIENT.

The correct answer is [spoiler]A[/spoiler].[/quote]

We know from table that
Total "Against A" : 40
Total "Against B" : 20

so, total "against" : 40 + 20 - both
: 60 - both

We know from Statement 2 that "both against" : 20

so, total "against" : 60 - 20 = 40

so, total "for" : 100 - 40 = 60

so, both "for" : 40 + 30 - 60 = 10

Hence, answer should be D

Pl tell where I am wrong?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members
Location: New York, NY
Thanked: 13060 times
GMAT Score:790

by GMATGuruNY » Sat Feb 18, 2012 8:03 am
ranjeet75 wrote:
We know from table that
Total "Against A" : 40
Total "Against B" : 20

so, total "against" : 40 + 20 - both
: 60 - both

We know from Statement 2 that "both against" : 20

so, total "against" : 60 - 20 = 40

so, total "for" : 100 - 40 = 60

so, both "for" : 40 + 30 - 60 = 10

Hence, answer should be D

Pl tell where I am wrong?
Since every student voted twice, the total number of votes = 200.

Statement 2 implies that the AGAINST votes are distributed as follows:
Image

There is no way to determine how the remaining votes are distributed.

The following distribution is possible:
Image
In this case, the number of students who voted for both A and B is 20.

The following distribution also is possible:
Image
In this case, the number of students who voted for both A and B is 0.

Since the number of students who voted for both A and B can be different values, INSUFFICIENT.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1