Foodmart customers regularly buy at least one of the : GMAT Problem Solving (PS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 21 Jan 2017, 13:59

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Foodmart customers regularly buy at least one of the

Author Message
TAGS:

### Hide Tags

Intern
Joined: 19 Dec 2009
Posts: 33
Followers: 0

Kudos [?]: 66 [1] , given: 9

### Show Tags

23 Dec 2010, 16:33
1
KUDOS
6
This post was
BOOKMARKED
00:00

Difficulty:

15% (low)

Question Stats:

78% (02:04) correct 22% (02:15) wrong based on 140 sessions

### HideShow timer Statistics

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%
[Reveal] Spoiler: OA
Math Expert
Joined: 02 Sep 2009
Posts: 36590
Followers: 7092

Kudos [?]: 93355 [0], given: 10557

Re: difficult overlapping sets problem [#permalink]

### Show Tags

23 Dec 2010, 16:39
rtaha2412 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%

100%={customers who buy milk}+{customers who buy chicken}+{customers who buy apples} - {customer who buy exactly 2 products} - 2*{customers who by exactly 3 products}+{customers who buy neither of the products}

$$100=60+50+35-x-2*10+0$$ --> $$x=25$$.

For more about the formulas for 3 overlapping sets please see my post at: formulae-for-3-overlapping-sets-69014.html?hilit=rather%20memorize

Also discussed here: m03-74439.html?hilit=chicken%20milk#p786229

Hope it helps.
_________________
Intern
Joined: 19 Dec 2009
Posts: 33
Followers: 0

Kudos [?]: 66 [0], given: 9

Re: difficult overlapping sets problem [#permalink]

### Show Tags

23 Dec 2010, 16:41
thanks alot i will check out that extra post
Retired Moderator
Joined: 03 Aug 2010
Posts: 246
Followers: 2

Kudos [?]: 37 [0], given: 41

Re: difficult overlapping sets problem [#permalink]

### Show Tags

23 Dec 2010, 21:51
@rtaha... the bunuel's approach of addressing this problem with formula is invincible, and is the best approach.

I was facing a lot of problems in set thory, i improved a lot by solving every problem 1) by formula of bunuel and 2) actual ven diagram
By solving this problems with ven diagram, you would basically learn why this formula is applied.
_________________

http://www.gmatpill.com/gmat-practice-test/

Amazing Platform

Senior Manager
Status: swimming against the current
Joined: 24 Jul 2009
Posts: 252
Location: Chennai, India
Followers: 4

Kudos [?]: 91 [0], given: 30

Re: difficult overlapping sets problem [#permalink]

### Show Tags

25 Dec 2010, 18:59
Bunuel wrote:
rtaha2412 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%

100%={customers who buy milk}+{customers who buy chicken}+{customers who buy apples} - {customer who buy exactly 2 products} - 2*{customers who by exactly 3 products}+{customers who buy neither of the products}

$$100=60+50+35-x-2*10+0$$ --> $$x=25$$.

For more about the formulas for 3 overlapping sets please see my post at: formulae-for-3-overlapping-sets-69014.html?hilit=rather%20memorize

Also discussed here: m03-74439.html?hilit=chicken%20milk#p786229

Hope it helps.

I have seen these 2 formulaes being used. What is the difference between them
P (A u B u C) = P (A) + P (B) + P (C) - [ P (A n B) + P (A n C) + P (B n C) ] + P (A n B n C)
and P (A u B u C) = P (A) + P (B) + P (C) - [ P (A n B) + P (A n C) + P (B n C) ] - 2(P (A n B n C))
_________________

Gonna make it this time

Math Expert
Joined: 02 Sep 2009
Posts: 36590
Followers: 7092

Kudos [?]: 93355 [1] , given: 10557

Re: difficult overlapping sets problem [#permalink]

### Show Tags

25 Dec 2010, 23:41
1
KUDOS
Expert's post
mailnavin1 wrote:
Bunuel wrote:
rtaha2412 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%

100%={customers who buy milk}+{customers who buy chicken}+{customers who buy apples} - {customer who buy exactly 2 products} - 2*{customers who by exactly 3 products}+{customers who buy neither of the products}

$$100=60+50+35-x-2*10+0$$ --> $$x=25$$.

For more about the formulas for 3 overlapping sets please see my post at: formulae-for-3-overlapping-sets-69014.html?hilit=rather%20memorize

Also discussed here: m03-74439.html?hilit=chicken%20milk#p786229

Hope it helps.

I have seen these 2 formulaes being used. What is the difference between them
P (A u B u C) = P (A) + P (B) + P (C) - [ P (A n B) + P (A n C) + P (B n C) ] + P (A n B n C)
and P (A u B u C) = P (A) + P (B) + P (C) - [ P (A n B) + P (A n C) + P (B n C) ] - 2(P (A n B n C))

_________________
Senior Manager
Status: swimming against the current
Joined: 24 Jul 2009
Posts: 252
Location: Chennai, India
Followers: 4

Kudos [?]: 91 [0], given: 30

Re: difficult overlapping sets problem [#permalink]

### Show Tags

26 Dec 2010, 00:21
Oops sorry, missed that one. Got it now thanks a ton
_________________

Gonna make it this time

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13488
Followers: 576

Kudos [?]: 163 [0], given: 0

### Show Tags

19 Dec 2015, 03:56
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.
_________________
Re: Foodmart customers regularly buy at least one of the   [#permalink] 19 Dec 2015, 03:56
Similar topics Replies Last post
Similar
Topics:
1 The original price of an item is discounted 20%. A customer buys the 1 05 May 2016, 14:48
1 Foodmart customers regularly buy at least one of the followi 4 02 Sep 2010, 07:47
Foodmart customers regularly buy at least one 3 29 Aug 2010, 15:38
1 Foodmart customers regularly buy at least one of the following product 4 02 Mar 2010, 18:45
Foodmart customers regularly buy at least one of the 12 27 Jan 2008, 22:20
Display posts from previous: Sort by