In how many different ways can 4 ladies and 4 gentlemen be

Oldest

Best Reply

Author

Message

TAGS:

Intern

Joined: 01 Sep 2010

Posts: 23

Followers: 1

Kudos [?]: 27 [2] , given: 8

In how many different ways can 4 ladies and 4 gentlemen be [#permalink]

04 Oct 2010, 06:40

This post received
KUDOS

00:00

Question Stats:

85% (01:20) correct

14% (01:47) wrong

based on 3 sessions

In how many different ways can 4 ladies and 4 gentlemen be seated at a round table so that all ladies sit together?

A. 70
B. 288
C. 576
D. 10,080
E. 20,160

[Reveal] Spoiler: OA

GMAT Club team member

Joined: 02 Sep 2009

Posts: 11532

Followers: 1795

Kudos [?]: 9551 [0], given: 826

Re: Ways to sit around the table [#permalink]

04 Oct 2010, 08:11

eladshush wrote:

In how many different ways can 4 ladies and 4 gentlemen be seated at a round table so that all ladies sit together?

A. 70
B. 288
C. 576
D. 10,080
E. 20,160

Glue the ladies together so that they create one unit, so we would have 5 units: {M1}, {M2}, {M3}, {M4}, and {W1,W2,W3,W4} --> # of different arrangements of n objects around the table (circular arrangements) is (n-1)!, so our 5 objects can be arranged in (5-1)!=4! ways.

On the other hand 4 women within their unit also can be arranged in 4! ways --> total 4!*4!=576.

Answer: C.
_________________

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. NEW!!!

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set. NEW!!!

What are GMAT Club Tests?
25 extra-hard Quant Tests

Find out what's new at GMAT Club - latest features and updates

Manager

Joined: 07 Oct 2006

Posts: 73

Location: India

Followers: 1

Kudos [?]: 6 [0], given: 3

Re: Ways to sit around the table [#permalink]

04 Oct 2010, 08:32

Good question... Yet another good explanation from the Master.....
_________________

-------------------------------------
Please give kudos, if my post is helpful.

For English Grammar tips, consider visiting http://www.grammar-quizzes.com/index.html.

Retired Moderator

Joined: 02 Sep 2010

Posts: 815

Location: London

Followers: 56

Kudos [?]: 301 [0], given: 25

Re: Ways to sit around the table [#permalink]

04 Oct 2010, 08:58

eladshush wrote:

In how many different ways can 4 ladies and 4 gentlemen be seated at a round table so that all ladies sit together?

A. 70
B. 288
C. 576
D. 10,080
E. 20,160

Treat the 4 ladies as one object, now you have 5 objects to arrange around a table (m1,m2,m3,m4,women). This can be done in (5-1)! ways
And there are 4! ways to arrange ladies among themselves

Answer = (4!)^2 = 576 or C
_________________

Math write-ups
1) Algebra-101 2) Sequences 3) Set combinatorics 4) 3-D geometry

My GMAT story

Find out what's new at GMAT Club - latest features and updates

Re: Ways to sit around the table [#permalink] 04 Oct 2010, 08:58

	Similar topics	Author	Replies	Last post
Similar Topics:	In how many different ways can 4 teachers and 4 students sit	emilem	3	01 Jun 2005, 04:38
	In how many ways can 4 identical red balls and 5 different	rchadha	10	05 Oct 2005, 15:47
	How many different ways can 12 employees be assigned to 4	chets	4	07 Oct 2005, 08:44
	In how many ways can 4 identical red balls and 5 different	gmacvik	5	20 Oct 2005, 19:45
	How many different ways can a group of 8 be divided into 4	21stCenturion	6	22 Jan 2006, 09:48

In how many different ways can 4 ladies and 4 gentlemen be

Main navigation

GMAT Resources

Partners

MBA Resources

GMAT ® is a registered trademark of the Graduate Management Admission Council ® (GMAC ®). GMAT Club's website has not been reviewed or endorsed by GMAC.

GMAT Courses

Admissions Consulting

In how many different ways can 4 ladies and 4 gentlemen be

In how many different ways can 4 ladies and 4 gentlemen be

Main navigation

GMAT Resources

Partners

MBA Resources