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

It is currently 22 Oct 2014, 04:48

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

Combinatorics, kaplan, 700 level, PS - unique 2 latter code

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Manager
Manager
avatar
Joined: 10 Jan 2011
Posts: 244
Location: India
GMAT Date: 07-16-2012
GPA: 3.4
WE: Consulting (Consulting)
Followers: 0

Kudos [?]: 21 [1] , given: 25

Reviews Badge
Combinatorics, kaplan, 700 level, PS - unique 2 latter code [#permalink] New post 16 Oct 2011, 10:03
1
This post received
KUDOS
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

43% (01:24) correct 57% (00:36) wrong based on 10 sessions
Each runner during a race is labeled with a unique one-letter code or a unique two-letter code, where the two letters are different. The codes use the 26-letter English alphabet, and if a given two letter code is used then the reverse code is not used. What is the maximum number of runners that can receive unique codes for the race?

A 325
B 351
C 677
D 650
E 676

guys please explain your answer I will provide OA after discussion
_________________

-------Analyze why option A in SC wrong-------


Last edited by 144144 on 17 Oct 2011, 00:39, edited 1 time in total.
Moved to the right place
1 KUDOS received
Manager
Manager
avatar
Joined: 21 Aug 2010
Posts: 93
Location: United States
Followers: 1

Kudos [?]: 26 [1] , given: 80

GMAT ToolKit User CAT Tests
Re: Combinatorics, kaplan, 700 level, PS - unique 2 latter code [#permalink] New post 19 Oct 2011, 10:53
1
This post received
KUDOS
nishtil wrote:
Each runner during a race is labeled with a unique one-letter code or a unique two-letter code, where the two letters are different. The codes use the 26-letter English alphabet, and if a given two letter code is used then the reverse code is not used. What is the maximum number of runners that can receive unique codes for the race?

A 325
B 351
C 677
D 650
E 676

guys please explain your answer I will provide OA after discussion


1. 26 one letter code can be given(equal to number of alphabets)
2. Two letter codes

Number of possible 2 letter codes is equal to the sum of all the numbers between 25 and 1 (sum first 25 digits)

i.e, n(n+1)/2 = 325

Maximum number of runners that can receive unique codes = 325+26 =351
Ans B
_________________

-------------------------------------

Re: Combinatorics, kaplan, 700 level, PS - unique 2 latter code   [#permalink] 19 Oct 2011, 10:53
    Similar topics Author Replies Last post
Similar
Topics:
1 Experts publish their posts in the topic PS Combinatorics Cityboy 5 24 Apr 2013, 13:11
2 Combinatorics, kaplan, 700 level, PS - unique 2 latter code nishtil 1 16 Oct 2011, 10:03
25 Experts publish their posts in the topic PS - Combinatorics (m02q05) yuefei 39 12 Nov 2007, 17:36
PS: Combinatorics.. ConkergMat 3 02 Mar 2009, 17:49
PS - Combinatorics gmatatouille 11 18 Dec 2008, 10:17
Display posts from previous: Sort by

Combinatorics, kaplan, 700 level, PS - unique 2 latter code

  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®.