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

It is currently 25 Apr 2018, 11:21

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

If 4 people are selected from a group of 6 married couples

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

Hide Tags

Manager
Manager
avatar
Joined: 29 Nov 2011
Posts: 111
Re: If 4 people are selected from a group of 6 married couples [#permalink]

Show Tags

New post 05 Apr 2016, 00:05
HI Bunnel

Number of ways to select...Atleast one married couple is

6C1- Choose 1 married couple for 2 seats
10C2- Chose 2 members from the remaining 5 couples for the remaining 2 seats

6C1*10C2= 270
No of ways to select 4 people from 12=12C4

P= 270/495

Answer=1- the prob of the above
=5/11

What am I missing here?
Manager
Manager
avatar
B
Joined: 01 Nov 2016
Posts: 69
Concentration: Technology, Operations
Re: If 4 people are selected from a group of 6 married couples [#permalink]

Show Tags

New post 27 Mar 2017, 21:51
What is the chance that four chosen have nobody married to each other? Well we want to find \(\frac{chance of success}{number of outcomes}\). Without using combitronics:

Chance of success is 12*10*8*6
Total outcomes are 12*11*9*8

\(\frac{12*10*8*6}{12*11*10*9}=\frac{8*6}{11*9}=\frac{16}{33}\)
Manager
Manager
avatar
B
Joined: 12 Nov 2016
Posts: 138
Concentration: Entrepreneurship, Finance
GMAT 1: 620 Q36 V39
GMAT 2: 650 Q47 V33
Re: If 4 people are selected from a group of 6 married couples [#permalink]

Show Tags

New post 16 Dec 2017, 08:51
metallicafan wrote:
+1 D

A faster way to solve it:

\(\frac{12}{12} * \frac{10}{11} * \frac{8}{10} * \frac{6}{9} = \frac{48}{99} = \frac{16}{33}\)


Isn't it a short and great approach? is there anything wrong with it? Why for problems like this is combinatorics a preferred approach?
1 KUDOS received
PS Forum Moderator
avatar
D
Joined: 25 Feb 2013
Posts: 1059
Location: India
GPA: 3.82
GMAT ToolKit User Premium Member Reviews Badge CAT Tests
Re: If 4 people are selected from a group of 6 married couples [#permalink]

Show Tags

New post 16 Dec 2017, 09:41
1
This post received
KUDOS
Erjan_S wrote:
metallicafan wrote:
+1 D

A faster way to solve it:

\(\frac{12}{12} * \frac{10}{11} * \frac{8}{10} * \frac{6}{9} = \frac{48}{99} = \frac{16}{33}\)


Isn't it a short and great approach? is there anything wrong with it? Why for problems like this is combinatorics a preferred approach?


Hi Erjan_S

There is nothing wrong with the approach. As the numbers are simple so you can simply count the possible and total outcomes and then keep on removing the pairs. There could be multiple ways to solve counting problems. P & C is preferred because you get the value through direct formula. in case of simple numbers you can manually count the number of possible ways or selections, but when the numbers or situation become a bit complex then you will have to rely upon P & C.
Re: If 4 people are selected from a group of 6 married couples   [#permalink] 16 Dec 2017, 09:41

Go to page   Previous    1   2   [ 24 posts ] 

Display posts from previous: Sort by

If 4 people are selected from a group of 6 married couples

  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®.