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

It is currently 25 Oct 2014, 06:34

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

There are 5 married couples and a group of three is to be

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 10 Oct 2004
Posts: 1
Followers: 0

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

There are 5 married couples and a group of three is to be [#permalink] New post 16 Oct 2004, 12:46
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
There are 5 married couples and a group of three is to be formed out of them; how many arrangements are there if a husband and wife may not be in the same group?

How many different signals can be transmitted by hoisting 3 red, 4 yellow and 2 blue flags on a pole, assuming that in transmitting a signal all nine flags are to be used?
Manager
Manager
avatar
Joined: 13 Oct 2004
Posts: 51
Followers: 0

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

 [#permalink] New post 16 Oct 2004, 13:07
1. All possible combn - (no of married couple) X (no of choice for third person)


10C3 - (5C1 X 8C1) = 120 - 40 = 80


2. 9 ! / (3! x 4 ! x 2 !) = 1260
Manager
Manager
User avatar
Joined: 24 Aug 2004
Posts: 66
Followers: 1

Kudos [?]: 3 [0], given: 0

 [#permalink] New post 17 Oct 2004, 07:40
1. let the 5 couples be represented as
A(H,W); B(H,W); C(H,W); D(H,W); E(H,W); where H represent Husband and W wife.

now out of these 5 grps, u have to select 3; only then u will get a group of mutually unmarried ppl; so that can be done in 5C3 ways. However from within a grp (A,b,c,d e) you can select either H or W. and that can be done in 2C1 ways.
SO the total no of ways = 5C3 * 2C1 = 10 * 2 = 20.

2. its a question of no of permutations of 9 things where 3 are of one type, 4 of the other and 2 of the third type and that is 9! / (3! * 4! * 2!) .... a huge number, not worth the type spending on calculation... :lol:
Manager
Manager
avatar
Joined: 18 Sep 2004
Posts: 157
Location: Dallas, TX
Followers: 1

Kudos [?]: 4 [0], given: 0

 [#permalink] New post 17 Oct 2004, 08:00
1) I get 120

Total number of 3 you can choice from a group of 10 (5 couples) = 10 C 3
Total number of groups of 3 where a H and W are in the same group. 8C1 * 5 (You can think of the HW as one, so out of the eight remaining choose 1, since there are 5 couples, the HW and be any one of the five)

10C3 - (8C1 * 5) = 120 - 40 - 80

2) Total 9 flags, = 9! Divide by non-unique (4!*3!*2!) = 9!/(4!*3!*2!) = 1260
Manager
Manager
avatar
Joined: 02 Jul 2004
Posts: 51
Followers: 0

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

 [#permalink] New post 17 Oct 2004, 12:14
For 1 ... I'm going with

M-M-M groups
5*4*3/3! = 10

+

F-F-F groups
5*4*3/3! = 10

+

M-M-F groups
5*4*3/2! = 30

+

F-F-M groups
5*4*3/2! = 30

Total is 80 ...

Additionally, I think that the previous post from Target780 is correct except that it should be
5C3 * 2^3 = 80
  [#permalink] 17 Oct 2004, 12:14
    Similar topics Author Replies Last post
Similar
Topics:
There are 5 married couples and a group of three is to be Dek 18 03 Jun 2007, 07:08
There are 5 married couples and a group of three is to be girikorat 1 09 Oct 2006, 10:21
There are 5 married couples and a group of three is to be GMATT73 7 28 Jan 2006, 23:27
There are 5 married couples and a group of three is to be JAI HIND 4 20 Dec 2005, 19:48
There are 5 married couples and a group of three is to be sk 15 06 Feb 2005, 16:55
Display posts from previous: Sort by

There are 5 married couples and a group of three is to be

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

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®.