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

It is currently 23 Jul 2014, 02:13

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

A research study found that, of 500 people surveyed, 220

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
User avatar
Joined: 28 May 2009
Posts: 155
Followers: 4

Kudos [?]: 81 [0], given: 89

GMAT ToolKit User
A research study found that, of 500 people surveyed, 220 [#permalink] New post 06 Mar 2013, 18:37
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  25% (low)

Question Stats:

73% (02:10) correct 27% (00:59) wrong based on 83 sessions
A research study found that, of 500 people surveyed, 220 watched neither Network A nor Network B, 120 watched only Network A, and for every person who watched both networks, 3 watched only Network B. How many of the 500 people surveyed watched both networks?

(A) 40
(B) 60
(C) 80
(D) 100
(E) 120

I always screw up with the correct usage of this relationship: [Total = Group1 + Group2 - Both + Neither] vs [Total = Group1 + Group2 + Both + Neither], i.e. when to subtract Both and when to add Both
[Reveal] Spoiler: OA

_________________

New to GMAT Club? Start here

Kindle Flashcards - Quant (Official Gmat Club, miguemick's Quant topics), and Verbal (Official Gmat Club) - in Kindle (azw3) format

1 KUDOS received
Director
Director
User avatar
Status:
Joined: 24 Jul 2011
Posts: 547
GMAT 1: 780 Q51 V48
GRE 1: 1540 Q800 V740
Followers: 60

Kudos [?]: 261 [1] , given: 11

Re: A research study found that, of 500 people surveyed, 220 [#permalink] New post 06 Mar 2013, 19:53
1
This post received
KUDOS
megafan, see the attached figure.

the portion in green corresponds to neither A nor B. The one in brown corresponds to only A. The one in blue to only B. The one in red to both A and B.

n(Total) = n(Neither A nor B) + n(only A) + n(only B) + n(both A and B)
=> 500 = 220 + 120 + 3x + x
=> x = 160/4 = 40

Therefore 40 people watched both networks.

Option A.

Attachments

figure.jpg
figure.jpg [ 28.56 KiB | Viewed 1188 times ]


_________________

GyanOne | http://www.GyanOne.com | +91 9899831738

Get a free detailed MBA profile evaluation

Top MBA Rankings and MBA Admissions blog


Image

Expert Post
2 KUDOS received
Veritas Prep GMAT Instructor
User avatar
Joined: 16 Oct 2010
Posts: 4566
Location: Pune, India
Followers: 1029

Kudos [?]: 4454 [2] , given: 162

Re: A research study found that, of 500 people surveyed, 220 [#permalink] New post 06 Mar 2013, 20:51
2
This post received
KUDOS
Expert's post
Here are the two formulas

1. [Total = Group1 + Group2 - Both + Neither]

Used when Group1 includes Both.
e.g. given 160 people watch network A. This means 160 watch network A and it includes those people who watch both the networks. Similarly, Group2 includes people who watch both the networks e.g. given 160 watch network B - 160 includes the number of people who watch both networks.
Since no of people who watch both networks is included twice, you subtract it out once.

500 = 160 + 160 - 40 + 220

2. [Total = Group1 + Group2 + Both + Neither]

Used when Group1 is the number of people who watch ONLY network A
e.g. given 120 people watch ONLY network A (compare this with above where the word ONLY is missing). Group2 includes people who watch ONLY network B. Since you haven't accounted for the people who watch both, you add Both once.

500 = 120 + 120 + 40 + 220

Hope both the formulas make sense now.

Here, you are given that 120 watched only network A so you use the second formula. Also, it might be a good idea to get comfortable with venn diagrams. Such confusions do not occur if you always use the venn diagram.

_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Save $100 on Veritas Prep GMAT Courses And Admissions Consulting
Enroll now. Pay later. Take advantage of Veritas Prep's flexible payment plan options.

Veritas Prep Reviews

Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18693
Followers: 3232

Kudos [?]: 22237 [1] , given: 2602

Re: A research study found that, of 500 people surveyed, 220 [#permalink] New post 07 Mar 2013, 00:52
1
This post received
KUDOS
Expert's post
megafan wrote:
A research study found that, of 500 people surveyed, 220 watched neither Network A nor Network B, 120 watched only Network A, and for every person who watched both networks, 3 watched only Network B. How many of the 500 people surveyed watched both networks?

(A) 40
(B) 60
(C) 80
(D) 100
(E) 120

I always screw up with the correct usage of this relationship: [Total = Group1 + Group2 - Both + Neither] vs [Total = Group1 + Group2 + Both + Neither], i.e. when to subtract Both and when to add Both


This might help: advanced-overlapping-sets-problems-144260.html (ADVANCED OVERLAPPING SETS PROBLEMS)

_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Manager
Manager
User avatar
Joined: 28 May 2009
Posts: 155
Followers: 4

Kudos [?]: 81 [0], given: 89

GMAT ToolKit User
Re: A research study found that, of 500 people surveyed, 220 [#permalink] New post 07 Mar 2013, 08:08
VeritasPrepKarishma wrote:
Here are the two formulas

1. [Total = Group1 + Group2 - Both + Neither]

Used when Group1 includes Both.
e.g. given 160 people watch network A. This means 160 watch network A and it includes those people who watch both the networks. Similarly, Group2 includes people who watch both the networks e.g. given 160 watch network B - 160 includes the number of people who watch both networks.
Since no of people who watch both networks is included twice, you subtract it out once.

500 = 160 + 160 - 40 + 220

2. [Total = Group1 + Group2 + Both + Neither]

Used when Group1 is the number of people who watch ONLY network A
e.g. given 120 people watch ONLY network A (compare this with above where the word ONLY is missing). Group2 includes people who watch ONLY network B. Since you haven't accounted for the people who watch both, you add Both once.

500 = 120 + 120 + 40 + 220

Hope both the formulas make sense now.

Here, you are given that 120 watched only network A so you use the second formula. Also, it might be a good idea to get comfortable with venn diagrams. Such confusions do not occur if you always use the venn diagram.


Wow, thanks a lot! This makes the problem seem like a 300-level question. I think I usually don't pay attention to the elements in the set -- i.e. whether there is an overlap or not. Note to self: watch out for only.

_________________

New to GMAT Club? Start here

Kindle Flashcards - Quant (Official Gmat Club, miguemick's Quant topics), and Verbal (Official Gmat Club) - in Kindle (azw3) format

Intern
Intern
avatar
Joined: 28 Nov 2012
Posts: 48
Followers: 0

Kudos [?]: 2 [0], given: 3

Re: A research study found that, of 500 people surveyed, 220 [#permalink] New post 08 Mar 2013, 14:38
and for every person who watched both networks, 3 watched only Network B. How many of the 500 people surveyed watched both networks?

Can someone clarify this wording? I understood what they were testing but I couldn't figure out what that meant....
Expert Post
Veritas Prep GMAT Instructor
User avatar
Joined: 16 Oct 2010
Posts: 4566
Location: Pune, India
Followers: 1029

Kudos [?]: 4454 [0], given: 162

Re: A research study found that, of 500 people surveyed, 220 [#permalink] New post 08 Mar 2013, 23:32
Expert's post
skiingforthewknds wrote:
and for every person who watched both networks, 3 watched only Network B. How many of the 500 people surveyed watched both networks?

Can someone clarify this wording? I understood what they were testing but I couldn't figure out what that meant....


It just gives you the relation between the two groups:

- No of people who watched both networks
- No of people who watched only network B

It means that if there is only 1 person who watches both networks, there are 3 who watch only network B. If there are 2 people who watch both networks, there are 6 who watch only network B and so on...
It is just another way of telling that the ratio of no of people watching both networks and no of people who watch only network B is 1:3

So if x people watch both networks, 3x watch only network B.

_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Save $100 on Veritas Prep GMAT Courses And Admissions Consulting
Enroll now. Pay later. Take advantage of Veritas Prep's flexible payment plan options.

Veritas Prep Reviews

Intern
Intern
avatar
Joined: 16 Dec 2012
Posts: 1
Followers: 0

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

Re: A research study found that, of 500 people surveyed, 220 [#permalink] New post 29 May 2013, 09:34
Can anyone solve the same problem using 2 way matrix
Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18693
Followers: 3232

Kudos [?]: 22237 [1] , given: 2602

Re: A research study found that, of 500 people surveyed, 220 [#permalink] New post 29 May 2013, 14:09
1
This post received
KUDOS
Expert's post
piyushdiyora wrote:
Can anyone solve the same problem using 2 way matrix


A research study found that, of 500 people surveyed, 220 watched neither Network A nor Network B, 120 watched only Network A, and for every person who watched both networks, 3 watched only Network B. How many of the 500 people surveyed watched both networks?
(A) 40
(B) 60
(C) 80
(D) 100
(E) 120
Attachment:
Matrix.png
Matrix.png [ 5.36 KiB | Viewed 622 times ]
From above 4x+340=500 --> x=40.

Answer: A.

Hope it helps.

_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
User avatar
Joined: 02 May 2013
Posts: 26
Concentration: International Business, Technology
WE: Engineering (Aerospace and Defense)
Followers: 1

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

Re: A research study found that, of 500 people surveyed, 220 [#permalink] New post 29 May 2013, 17:57
let x = only A =120 given
y = both A and B
z=only B
w= neither A and B = 220 given
also given z=3*y

from below picture
x+y+z+w = 500
using above given values
y+z =160

and 4*y = 160(since z=3*y)
y=40

Sol:A

Attachments

venn_1.JPG
venn_1.JPG [ 7.66 KiB | Viewed 593 times ]

SVP
SVP
User avatar
Joined: 09 Sep 2013
Posts: 1710
Followers: 162

Kudos [?]: 33 [0], given: 0

Premium Member
Re: A research study found that, of 500 people surveyed, 220 [#permalink] New post 19 Jun 2014, 07:07
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.

_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Re: A research study found that, of 500 people surveyed, 220   [#permalink] 19 Jun 2014, 07:07
    Similar topics Author Replies Last post
Similar
Topics:
3 Of the 500 business people surveyed, 78 percent said that SreeViji 4 01 Dec 2012, 01:11
1 Experts publish their posts in the topic A researcher studying corporate executives found that they GetThisDone 4 28 Apr 2012, 20:09
a researcher studying drug addicts found that,on AK47 5 13 Oct 2006, 01:24
A researcher studying drug addicts found that, on average, govinam 16 18 Sep 2006, 15:11
In a survey of 140 people it was found that 115 people AJB77 3 02 Jul 2005, 07:01
Display posts from previous: Sort by

A research study found that, of 500 people surveyed, 220

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

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®.