The table above shows the results of a survey of 100 voters each responded "favorable" or "unfavorable" or "not sure" when asked about their impressions of candidate M and of candidate N.
What was the number of voters who responded "favorable" for both candidates?
(1) The number of voters who did not respond "favorable" for either candidate was 40.
(2) The number of voters who responded "unfavorable" for both candidates was 10
{A}
Results of a survey of 100 voters - Nice Question
This topic has expert replies
- theCodeToGMAT
- Legendary Member
- Posts: 1556
- Joined: Tue Aug 14, 2012 11:18 pm
- Thanked: 448 times
- Followed by:34 members
- GMAT Score:650
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
- Attachments
-
R A H U L
- GMATGuruNY
- GMAT Instructor
- Posts: 15539
- Joined: Tue May 25, 2010 12:04 pm
- Location: New York, NY
- Thanked: 13060 times
- Followed by:1906 members
- GMAT Score:790
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
Total Favorable = Favorable for M + Favorable for N - Favorable for BothFavorable Unfavorable Not sure
Candidate M 40 20 40
Candidate N 30 35 35
The table above shows the results of a survey of 100 voters each responded favorable or unfavorable or not sure when asked about their impressions of candidate M and of candidate N. What was the number of voters who responded favorable for both candidates?
(1) The number of voters who did not respond favorable for either candidate was 40.
(2) The number of voters who responded unfavorable for both candidates was 10.
The big idea with overlapping group problems is to SUBTRACT THE OVERLAP.
When we count the number who responded Favorable for M and the number who responded Favorable for N, the number who responded Favorable for BOTH -- the OVERLAP -- gets counted twice.
So that we don't double-count the overlap, it must be SUBTRACTED from the total.
Since Favorable for M = 40 and Favorable for N = 30, we get:
Total = 40 + 30 - both
Both = 70 - total.
Question rephrased: What was the TOTAL number who responded Favorable?
Statement 1: The number of voters who did not respond favorable for either candidate was 40.
Since 40 did NOT respond Favorable, the total number who DID respond Favorable = 100-40 = 60.
SUFFICIENT.
Statement 2: The number of voters who responded unfavorable for both candidates was 10.
No way to determine the total number who responded Favorable.
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
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
-
- Master | Next Rank: 500 Posts
- Posts: 468
- Joined: Mon Jul 25, 2011 10:20 pm
- Thanked: 29 times
- Followed by:4 members
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
Not favorable to both = 40
Remove overlapping to get either or = 20 + 40 + 35 + 35 - 40 (Both) = 90
So 90 are those who says not favorable (including Unfavorable or Not sure) to either M or N
Favorable to both M and N = 100 - 90 = 10
OA A
Remove overlapping to get either or = 20 + 40 + 35 + 35 - 40 (Both) = 90
So 90 are those who says not favorable (including Unfavorable or Not sure) to either M or N
Favorable to both M and N = 100 - 90 = 10
OA A
GMAT/MBA Expert
- lunarpower
- GMAT Instructor
- Posts: 3380
- Joined: Mon Mar 03, 2008 1:20 am
- Thanked: 2256 times
- Followed by:1535 members
- GMAT Score:800
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
For statement 1, it helps to realize that the distinction between "unfavorable" and "not sure" is no longer a real distinction; all that matters is "favorable" or NOT "favorable".
Once you have that, you can make the usual two-way table for overlapping sets.
On the columns, "M favorable", "M not favorable", "total".
On the rows, "N favorable", "N not favorable", "total".
The information in statement 2 doesn't distinguish in any way between the "favorable" people (in whom we are interested) and the "not sure" people (in whom we aren't).
Once you have that, you can make the usual two-way table for overlapping sets.
On the columns, "M favorable", "M not favorable", "total".
On the rows, "N favorable", "N not favorable", "total".
The information in statement 2 doesn't distinguish in any way between the "favorable" people (in whom we are interested) and the "not sure" people (in whom we aren't).
Ron has been teaching various standardized tests for 20 years.
--
Pueden hacerle preguntas a Ron en castellano
Potete chiedere domande a Ron in italiano
On peut poser des questions à Ron en français
Voit esittää kysymyksiä Ron:lle myös suomeksi
--
Quand on se sent bien dans un vêtement, tout peut arriver. Un bon vêtement, c'est un passeport pour le bonheur.
Yves Saint-Laurent
--
Learn more about ron
--
Pueden hacerle preguntas a Ron en castellano
Potete chiedere domande a Ron in italiano
On peut poser des questions à Ron en français
Voit esittää kysymyksiä Ron:lle myös suomeksi
--
Quand on se sent bien dans un vêtement, tout peut arriver. Un bon vêtement, c'est un passeport pour le bonheur.
Yves Saint-Laurent
--
Learn more about ron