GMAT Changed on April 16th - Read about the latest changes here

It is currently 23 Apr 2018, 08:13

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

There are 8 magazines lying on a table; 4 are fashion

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

1 KUDOS received
Manager
Manager
avatar
Joined: 10 Oct 2008
Posts: 56
There are 8 magazines lying on a table; 4 are fashion [#permalink]

Show Tags

New post 10 Oct 2008, 13:12
1
This post received
KUDOS
10
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

81% (01:14) correct 19% (01:38) wrong based on 296 sessions

HideShow timer Statistics

There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines. If 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected?

A. 1/2
B. 2/3
C. 32/35
D. 11/12
E. 13/14
[Reveal] Spoiler: OA
Manager
Manager
avatar
Joined: 15 Apr 2008
Posts: 159
Re: magazine [#permalink]

Show Tags

New post 10 Oct 2008, 13:35
Jcpenny wrote:
There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines. If 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected?

A. 1/2
B. 2/3
C. 32/35
D. 11/12
E. 13/14


answer is E

Total probability=8C3=56
4C3 +4C2*4C1+4C1*4C2=4+24+24=52

therefore the probability that at least one of the fashion magazines will be selected= 52/56=13/14
Manager
Manager
User avatar
Joined: 06 Feb 2010
Posts: 162
Concentration: Marketing, Leadership
Schools: University of Dhaka - Class of 2010
GPA: 3.63
WE: Business Development (Consumer Products)
There are 8 magazines lying on a table; 4 are fashion [#permalink]

Show Tags

New post 20 Oct 2010, 05:45
1
This post was
BOOKMARKED
There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines. if 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected?

A. 1/2
B. 2/3
C. 32/35
D. 11/12
E. 13/14
_________________

Practice Makes a Man Perfect. Practice. Practice. Practice......Perfectly

Critical Reasoning: http://gmatclub.com/forum/best-critical-reasoning-shortcuts-notes-tips-91280.html

Collections of MGMAT CAT: http://gmatclub.com/forum/collections-of-mgmat-cat-math-152750.html

MGMAT SC SUMMARY: http://gmatclub.com/forum/mgmat-sc-summary-of-fourth-edition-152753.html

Sentence Correction: http://gmatclub.com/forum/sentence-correction-strategies-and-notes-91218.html

Arithmatic & Algebra: http://gmatclub.com/forum/arithmatic-algebra-93678.html

Helpful Geometry formula sheet: http://gmatclub.com/forum/best-geometry-93676.html


I hope these will help to understand the basic concepts & strategies. Please Click ON KUDOS Button.

Expert Post
5 KUDOS received
Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8030
Location: Pune, India
Re: Magazines probability [#permalink]

Show Tags

New post 20 Oct 2010, 07:07
5
This post received
KUDOS
Expert's post
10
This post was
BOOKMARKED
'At least 1' questions are best done by finding the complement i.e. I find the probability of selecting no fashion magazine and subtract that from 1 to get the probability of selecting at least 1 fashion magazine.

So I ask myself, what is the probability of selecting 3 sports magazines?
Since 4 of the 8 are sports magazines, probability of picking a sports mag is 1/2.
Probability of picking a second sports mag becomes 3/7. (because only 3 are left)
Probability of picking a third sports mag becomes 2/6. (Now only 2 sports mags are left)
Hence probability of picking 3 sports mags = 1/2 x 3/7 x 2x6 = 1/14

Then, probability of picking at least one fashion magazine will be 1 - 1/14 = 13/14
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Manager
Manager
avatar
Joined: 03 Jun 2010
Posts: 155
Location: United States (MI)
Concentration: Marketing, General Management
WE: Business Development (Consumer Products)
GMAT ToolKit User Reviews Badge
Re: Magazines probability [#permalink]

Show Tags

New post 20 Oct 2010, 08:08
Another approach:
1-3C4/3C8= 13/14
Where 3C4/3C8 is a probability to choose only sports mags (no fashion). When we substract it from 1, we get at least 1 fashion mag.
3C8 - total number of possibilities to choose 3 mags from 8.
3C4 - number of possibilities to choose only sports magazines.
Director
Director
User avatar
Status: No dream is too large, no dreamer is too small
Joined: 14 Jul 2010
Posts: 559
Re: magazine [#permalink]

Show Tags

New post 02 Jan 2012, 22:09
8c3 = 56
Probability of other magazines = 4/56 = 1/14
Probability of one FASHION magazine = 1-1/14 = 13/14
Ans. E
_________________

Collections:-
PSof OG solved by GC members: http://gmatclub.com/forum/collection-ps-with-solution-from-gmatclub-110005.html
DS of OG solved by GC members: http://gmatclub.com/forum/collection-ds-with-solution-from-gmatclub-110004.html
100 GMAT PREP Quantitative collection http://gmatclub.com/forum/gmat-prep-problem-collections-114358.html
Collections of work/rate problems with solutions http://gmatclub.com/forum/collections-of-work-rate-problem-with-solutions-118919.html
Mixture problems in a file with best solutions: http://gmatclub.com/forum/mixture-problems-with-best-and-easy-solutions-all-together-124644.html

Expert Post
Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8030
Location: Pune, India
Re: magazine [#permalink]

Show Tags

New post 03 Jan 2012, 02:53
Expert's post
2
This post was
BOOKMARKED
Jcpenny wrote:
There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines. If 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected?

A. 1/2
B. 2/3
C. 32/35
D. 11/12
E. 13/14


The 'at least' questions are best solved using the p(A) = 1 - p(A') approach.
If you want to find the probability that at least one of the fashion magazines is selected, instead find the probability that no fashion magazines are selected. Subtract that probability from 1 and you will get the probability that at least one fashion magazine is selected.
P(No fashion magazine selected) = No. of ways of selecting only sports magazines/Total no. of ways of selecting 3 magazines out of 8
No. of ways of selecting only sports magazines = 4C3 = 4
Total no. of ways of selecting 3 magazines out of 8 =*2* 8C3 = 8*7*6/(3*2*1) = 56
P(No fashion magazine selected) = 4/56 = 1/14

P(At least one fashion magazine is selected) = 1 - (1/14) = 13/14
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

1 KUDOS received
Manager
Manager
avatar
Joined: 22 Sep 2011
Posts: 208
GMAT 1: 720 Q49 V40
Re: magazine [#permalink]

Show Tags

New post 04 Jan 2012, 12:46
1
This post received
KUDOS
1-(4/8)*(3/7)*(2/6)
Intern
Intern
avatar
Joined: 11 Jul 2012
Posts: 41
Re: Magazines probability [#permalink]

Show Tags

New post 17 Oct 2012, 03:54
I found the following (rephrasing: what's the probability that we have one, two or three drawn from fashion magazines)
-number of total outcomes 3C8 = 8*7
-number of cases under consideration: 1C4*2C4 + 2C4*1C4 + 3C3*0C3 = 7*7
Answer 7*7/8*7 = 7/8.
What am I doing wrong
Brother Karamazov
Director
Director
User avatar
Joined: 22 Mar 2011
Posts: 607
WE: Science (Education)
Re: Magazines probability [#permalink]

Show Tags

New post 17 Oct 2012, 05:11
Ousmane wrote:
I found the following (rephrasing: what's the probability that we have one, two or three drawn from fashion magazines)
-number of total outcomes 3C8 = 8*7
-number of cases under consideration: 1C4*2C4 + 2C4*1C4 + 3C3*0C3 = 7*7
Answer 7*7/8*7 = 7/8.
What am I doing wrong
Brother Karamazov


It should be 1C4*2C4 + 2C4*1C4 + 3C4*0C4, which gives 52 and 52/56 = 13/14.
_________________

PhD in Applied Mathematics
Love GMAT Quant questions and running.

1 KUDOS received
VP
VP
User avatar
Joined: 02 Jul 2012
Posts: 1197
Location: India
Concentration: Strategy
GMAT 1: 740 Q49 V42
GPA: 3.8
WE: Engineering (Energy and Utilities)
Premium Member
Re: There are 8 magazines lying on a table; 4 are fashion [#permalink]

Show Tags

New post 17 Oct 2012, 05:15
1
This post received
KUDOS
1
This post was
BOOKMARKED
monirjewel wrote:
There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines. if 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected?

A. 1/2
B. 2/3
C. 32/35
D. 11/12
E. 13/14


Total no. of ways = \(8C3\) = 56

Favourable outcomes = 1 fashion & 2 sports, 2 fashion & 1 sports, 3 fashion
= \((4C1 * 4C2) + (4C2 * 4C1) + (4C3)\)
= 24 + 24 + 4
= 52

Probability = 52/56 = 13/14
_________________

Did you find this post helpful?... Please let me know through the Kudos button.

Thanks To The Almighty - My GMAT Debrief

GMAT Reading Comprehension: 7 Most Common Passage Types

Intern
Intern
avatar
B
Joined: 04 Feb 2017
Posts: 1
Re: There are 8 magazines lying on a table; 4 are fashion [#permalink]

Show Tags

New post 09 Apr 2017, 12:49
What is wrong with the below solution?
P(Selecting 1 among fashion) * P(selecting 2 books among the rest 7) / P(total cases)
(4C1*7C2)/8C3
Expert Post
Target Test Prep Representative
User avatar
G
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 2447
Location: United States (CA)
Re: There are 8 magazines lying on a table; 4 are fashion [#permalink]

Show Tags

New post 13 Mar 2018, 17:06
Expert's post
1
This post was
BOOKMARKED
Jcpenny wrote:
There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines. If 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected?

A. 1/2
B. 2/3
C. 32/35
D. 11/12
E. 13/14


We can use the formula:

P(at least one fashion magazine selected) = 1 - P(no fashion magazines are selected)

The number of ways to select 3 non-fashion magazines is 4C3 = 4!/[3!(4-3)!] = 4!/3! = 4 ways.

The number of ways to select 3 magazines from 8 is:

8C3 = 8!/[3!(8 - 3)!] = 8!/[3!5!] = (8 x 7 x 6)/( 3 x 2) = = 56 ways

So P(at least one fashion magazine selected) = 1 - 4/56 = 52/56 = 13/14.

Alternate Solution:

We can use the formula:

P(at least one fashion magazine selected) = 1 - P(no fashion magazines are selected)

The probability that no fashion magazines are selected is the same as saying that only sports magazines were selected, which is: 4/8 x 3/7 x 2/6 = 24/336 = 4/56 = 1/14.

Thus, P(at least one fashion magazine selected) = 1 - 1/14 = 14/14 - 1/14 = 13/14.

Answer: E
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Re: There are 8 magazines lying on a table; 4 are fashion   [#permalink] 13 Mar 2018, 17:06
Display posts from previous: Sort by

There are 8 magazines lying on a table; 4 are fashion

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.