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

It is currently 18 Sep 2014, 08:04

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

Probability - Business School

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Senior Manager
Senior Manager
avatar
Joined: 24 Mar 2011
Posts: 469
Location: Texas
Followers: 4

Kudos [?]: 56 [1] , given: 20

Probability - Business School [#permalink] New post 06 Jun 2011, 19:38
1
This post received
KUDOS
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

50% (01:42) correct 50% (01:15) wrong based on 6 sessions
A certain business school has 500 students, and the law school at the same university has 800 students. Among these students, there are 30 sibling pairs consisting of 1 business student and 1 law student. If 1 student is selected at random from both schools, what is the probability that a sibling pair is selected?

3/40,000
3/20,000
3/4,000
9/400
6/130

In the above Q, what the green color text means? i think it means 2 students (pair) to be selected from the gang since it is mentioned in the red that sibling pair is selected but i just thought that green text is missing 'each'.
Math Forum Moderator
avatar
Joined: 20 Dec 2010
Posts: 2047
Followers: 128

Kudos [?]: 925 [0], given: 376

GMAT Tests User
Re: Probability - Business School [#permalink] New post 07 Jun 2011, 00:58
agdimple333 wrote:
A certain business school has 500 students, and the law school at the same university has 800 students. Among these students, there are 30 sibling pairs consisting of 1 business student and 1 law student. If 1 student is selected at random from both schools, what is the probability that a sibling pair is selected?

3/40,000
3/20,000
3/4,000
9/400
6/130

In the above Q, what the green color text means? i think it means 2 students (pair) to be selected from the gang since it is mentioned in the red that sibling pair is selected but i just thought that green text is missing 'each'.


Good point agdimple333:
I prefer the wordings of the following link:
probability-57997.html

The use of word "both" and "pair" indeed creates some ambiguity as to whether we need to choose 2 students from each class OR 1 student from both classes combined.

Let's see using both scenarios:
If 2 students, 1 from each class, need to be selected.
P(Pick Sibling Pair)=(30/500)*(1/800)=30/400000= 3/40000

If just 1 student needs to be selected,
P(Pick from Sibling Pairs)=(30+30)/(500+800)=60/1300=6/130
_________________

~fluke

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Senior Manager
Senior Manager
avatar
Joined: 24 Mar 2011
Posts: 469
Location: Texas
Followers: 4

Kudos [?]: 56 [0], given: 20

Re: Probability - Business School [#permalink] New post 07 Jun 2011, 05:51
thank you and the correct answer is A.
Manager
Manager
avatar
Joined: 08 Sep 2010
Posts: 171
Followers: 0

Kudos [?]: 15 [0], given: 18

GMAT Tests User
Re: Probability - Business School [#permalink] New post 11 Jun 2011, 08:10
fluke,

don't you have your definitions reversed? you say 2 students and select only 30 and then you say 1 student and select (30+ 30).
I might be mistaken.

Let's see using both scenarios:
If 2 students, 1 from each class, need to be selected.
P(Pick Sibling Pair)=(30/500)*(1/800)=30/400000= 3/40000

If just 1 student needs to be selected,
P(Pick from Sibling Pairs)=(30+30)/(500+800)=60/1300=6/130
_________________

My will shall shape the future. Whether I fail or succeed shall be no man's doing but my own.

If you like my explanations award kudos.

Current Student
avatar
Joined: 26 May 2005
Posts: 571
Followers: 18

Kudos [?]: 110 [0], given: 13

GMAT Tests User
Re: Probability - Business School [#permalink] New post 11 Jun 2011, 08:28
Hi Puneet,
What Fluke has done is right..
there are 30 pairs of siblings( total 60; 30 in each class)
so selecting one is 500 students is 30/500
now that we have selected 1 sibling - selection of his/her partner is pretty easy
we need to get only that partner out of 30 siblings in 800 students
so its 1/800

together 30/400000 = 3/40000


selecting one student can be done ;

30 pairs = 60 student .
selecting one is 60C1
total 800+500 = 1300
one of 1300 is 1300C1
hence prob= 60c1/1300c1 = 6/130
Manager
Manager
avatar
Joined: 08 Sep 2010
Posts: 171
Followers: 0

Kudos [?]: 15 [0], given: 18

GMAT Tests User
Re: Probability - Business School [#permalink] New post 11 Jun 2011, 08:43
thanks Sudhir..got it
_________________

My will shall shape the future. Whether I fail or succeed shall be no man's doing but my own.

If you like my explanations award kudos.

Director
Director
avatar
Joined: 01 Feb 2011
Posts: 770
Followers: 14

Kudos [?]: 82 [0], given: 42

GMAT Tests User
Re: Probability - Business School [#permalink] New post 11 Jun 2011, 10:40
1 student from the both the schools translates to 1 from each school.

agdimple333 wrote:
A certain business school has 500 students, and the law school at the same university has 800 students. Among these students, there are 30 sibling pairs consisting of 1 business student and 1 law student. If 1 student is selected at random from both schools, what is the probability that a sibling pair is selected?

3/40,000
3/20,000
3/4,000
9/400
6/130

In the above Q, what the green color text means? i think it means 2 students (pair) to be selected from the gang since it is mentioned in the red that sibling pair is selected but i just thought that green text is missing 'each'.
Manager
Manager
avatar
Joined: 14 Feb 2011
Posts: 70
Followers: 1

Kudos [?]: 1 [0], given: 2

GMAT ToolKit User
Re: Probability - Business School [#permalink] New post 08 Aug 2011, 12:50
Hi, guys. So what is the right answer?

My method.
I understand the question that we take 1 person from each group.
P(person has a sibling in another group)=30/500
P(2nd group person is sibling)=1/800.

Multiply=30/40 000 or 3/4000

Am I right?
Re: Probability - Business School   [#permalink] 08 Aug 2011, 12:50
    Similar topics Author Replies Last post
Similar
Topics:
Experts publish their posts in the topic durham business school or Nottingham business school?? jatin781 1 09 Apr 2014, 13:03
1 Probability of Getting into Business School Michmax3 9 23 Sep 2010, 09:26
3 A typical busy day at business school.... refurb 9 25 Sep 2009, 14:02
1 PS-Probability -school club vivektripathi 3 07 Dec 2008, 02:22
Rutgers Business School vs Lubin Business School? oliverm 2 20 Nov 2007, 18:34
Display posts from previous: Sort by

Probability - Business School

  Question banks Downloads My Bookmarks Reviews Important topics  


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®.