2, 2, 7 and 9 be arranged

This topic has expert replies
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

2, 2, 7 and 9 be arranged

by sanju09 » Wed Feb 29, 2012 12:12 am
In how many different ways can the digits 2, 2, 7 and 9 be arranged, so that there is at least one 2 between 7 and 9 always?
A. 3
B. 4
C. 6
D. 9
E. 12
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Wed Feb 29, 2012 12:40 am
sanju09 wrote:In how many different ways can the digits 2, 2, 7 and 9 be arranged, so that there is at least one 2 between 7 and 9 always?
A. 3
B. 4
C. 6
D. 9
E. 12
The possible arrangements are:

Case 1: When 1st digit is 2.
2729, 2927

Case 2: When 1st digit is 7.
7292, 7229

Case 2: When 1st digit is 9.
9272, 9227

Therefore, required number of ways = 2 + 2 + 2 = 6

The correct answer is C.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/