Find all School-related info fast with the new School-Specific MBA Forum
Learn more about the recent changes... close

It is currently 24 May 2013, 12:31
Customize  |  Hide

Search
Register
New posts
Unanswered

GClub M03, Question 7/37 - 3 overlapping sets

  Question banks Downloads My Bookmarks Reviews  
  Oldest Best Reply
Search for:
 
Print view
First unread post
Author Message
TAGS:
Senior Manager
Senior Manager
User avatar
Joined: 21 Jul 2009
Posts: 371
Schools: LBS, INSEAD, IMD, ISB - Anything with just 1 yr program.
Followers: 11

Kudos [?]: 74 [0], given: 22

GMAT Tests User
GClub M03, Question 7/37 - 3 overlapping sets [#permalink] New post 02 Mar 2010, 19:45
00:00

Question Stats:

99% (01:50) correct 0% (00:00) wrong based on 2 sessions
Foodmart customers regularly buy at least one of the following products: milk, chicken, or apples. 60% of shoppers buy milk, 50% buy chicken, and 35% buy apples. If 10% of the customers buy all 3 products, what percentage of Foodmart customers purchase exactly 2 of the products listed above?

A) 5%
B) 10%
C) 15%
D) 25%
E) 30%

I am not convinced with the explanation given. There was also an alternative explanation, which wasn't very clear either -

Even though this is not a typical 2-group problem with overlapping members, we can still apply the group formula: Total = G1 + G2 + N - B, where G1, G2 are group 1 and group 2, N is neither, and B is both. Because we have more than 2 groups, we need to adjust the formula to reflect customers purchasing 3 products and therefore being members of 3 groups, and being counted as 3 distinct customers. The formula needs to be modified as follows: Total = G1 + G2 + G3 + N - B - T*(3-1) , where T is members of three groups and B is members of only two groups.

There is no neither group because all customers purchase at least one product.
The correct answer is D.

I suspect the formula for three overlapping sets used in the question. Can someone confirm it.
_________________

I am AWESOME and it's gonna be LEGENDARY!!!

Senior Manager
Senior Manager
Joined: 01 Feb 2010
Posts: 275
Followers: 1

Kudos [?]: 30 [0], given: 2

GMAT Tests User
Re: GClub M03, Question 7/37 - 3 overlapping sets [#permalink] New post 02 Mar 2010, 21:36
BarneyStinson wrote:
Foodmart customers regularly buy at least one of the following products: milk, chicken, or apples. 60% of shoppers buy milk, 50% buy chicken, and 35% buy apples. If 10% of the customers buy all 3 products, what percentage of Foodmart customers purchase exactly 2 of the products listed above?

A) 5%
B) 10%
C) 15%
D) 25%
E) 30%

I am not convinced with the explanation given. There was also an alternative explanation, which wasn't very clear either -

Even though this is not a typical 2-group problem with overlapping members, we can still apply the group formula: Total = G1 + G2 + N - B, where G1, G2 are group 1 and group 2, N is neither, and B is both. Because we have more than 2 groups, we need to adjust the formula to reflect customers purchasing 3 products and therefore being members of 3 groups, and being counted as 3 distinct customers. The formula needs to be modified as follows: Total = G1 + G2 + G3 + N - B - T*(3-1) , where T is members of three groups and B is members of only two groups.

There is no neither group because all customers purchase at least one product.
The correct answer is D.

I suspect the formula for three overlapping sets used in the question. Can someone confirm it.


The formula is
n(AUBUC) = n(A)+n(B)+n(C)-B+A-N
where B is both (it will sum of (A&B), (B&C), (C&A)).
and A is All
and N is neither
so plugging in we get
100 = 60+50+35+10-B-0
B = 55.
exactly two = 55 - 3(10) = 25
subtracting 10% three times as this value is including in all the (A&B), (B&C), (C&A).
Senior Manager
Senior Manager
User avatar
Joined: 21 Jul 2009
Posts: 371
Schools: LBS, INSEAD, IMD, ISB - Anything with just 1 yr program.
Followers: 11

Kudos [?]: 74 [0], given: 22

GMAT Tests User
Re: GClub M03, Question 7/37 - 3 overlapping sets [#permalink] New post 04 Mar 2010, 22:01
bangalorian2000 wrote:
The formula is
n(AUBUC) = n(A)+n(B)+n(C)-B+A-N
where B is both (it will sum of (A&B), (B&C), (C&A)).
and A is All
and N is neither
so plugging in we get
100 = 60+50+35+10-B-0
B = 55.
exactly two = 55 - 3(10) = 25
subtracting 10% three times as this value is including in all the (A&B), (B&C), (C&A).


Gotcha bro!!! You are indeed smart!!!
_________________

I am AWESOME and it's gonna be LEGENDARY!!!

Re: GClub M03, Question 7/37 - 3 overlapping sets   [#permalink] 04 Mar 2010, 22:01
    Similar topics Author Replies Last post
Similar
Topics:
 Popular new posts 85 EXPERTS_POSTS_IN_THIS_TOPIC Formulae for 3 overlapping sets amitdgr 43 12 Sep 2008, 03:41
Popular new posts 2 M03 #24 DS Question topmbaseeker 17 09 Dec 2008, 16:09
New posts 5 3 overlapping sets Hussain15 5 12 Jul 2010, 07:07
New posts 1 EXPERTS_POSTS_IN_THIS_TOPIC Unique Overlapping Set Question m990540 4 30 Jan 2011, 19:26
New posts EXPERTS_POSTS_IN_THIS_TOPIC m03 # 11 question utlnghrn34 3 29 Jun 2011, 06:52
Display posts from previous: Sort by

GClub M03, Question 7/37 - 3 overlapping sets

  Question banks Downloads My Bookmarks Reviews  
Print view
First unread post

Moderators: Bunuel, VeritasPrepKarishma, IanStewart

Search for:


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®.

Main navigation

GMAT Resources

Partners

MBA Resources

www.gmac.com|www.mba.com