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

It is currently 12 Jul 2014, 23:09

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

A researcher plans to identify each participant in a certain

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Manager
Manager
User avatar
Joined: 07 Jun 2006
Posts: 113
Followers: 2

Kudos [?]: 2 [1] , given: 0

A researcher plans to identify each participant in a certain [#permalink] New post 17 Nov 2006, 10:07
1
This post received
KUDOS
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

61% (01:48) correct 38% (00:42) wrong based on 42 sessions
A researcher plans to identify each participant in a certain medical experiment with a code consisting of either a single letter or a pair of distinct letters written in alphabetical order. What is the least number of letters that can be used if there are 12 participants, and each participant is to receive a different code?

A. 4
B. 5
C. 6
D. 7
E. 8

OPEN DISCUSSION OF THIS QUESTION IS HERE: a-researcher-plans-to-identify-each-participant-in-a-certain-134584.html
[Reveal] Spoiler: OA

Last edited by Bunuel on 16 Dec 2012, 22:52, edited 1 time in total.
Renamed the topic, edited the question and moved to PS forum.
Kaplan Promo CodeKnewton GMAT Discount CodesVeritas Prep GMAT Discount Codes
Director
Director
avatar
Joined: 12 Jun 2006
Posts: 539
Followers: 1

Kudos [?]: 8 [0], given: 1

GMAT Tests User
 [#permalink] New post 17 Nov 2006, 10:51
A researcher plans to identify each participant in a certain medical experiment with a
code consisting of either a single letter or a pair of distinct letters written in alphabetical
order. What is the least number of letters that can be used if there are 12 participants, and
each participant is to receive a different code?
A. 4
B. 5
C. 6
D. 7
E. 8

I think the order matters so I'm going w/B. I reasoned this one out.
Does "a pair of distinct letters written in alphabetical order" mean anything significant?

1 2 3 4 5 6 7 8 9 10 11 12
A B C D E AA AB AC AD AE BA BB

Last edited by ggarr on 17 Nov 2006, 11:26, edited 3 times in total.
Senior Manager
Senior Manager
avatar
Joined: 08 Jun 2006
Posts: 343
Location: Washington DC
Followers: 1

Kudos [?]: 11 [0], given: 0

GMAT Tests User
 [#permalink] New post 17 Nov 2006, 11:13
Getting 5

Bcos 5C2 + 5 = 15
using 4 we can reach up to 4C2 + 4 = 10
Manager
Manager
avatar
Joined: 04 Jan 2006
Posts: 58
Followers: 1

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

 [#permalink] New post 17 Nov 2006, 11:15
5
1 2 3 4 5 6 7 8 9 10 11 12
A B AB C AC BC D AD BD CD E AE
Senior Manager
Senior Manager
avatar
Joined: 20 Feb 2006
Posts: 375
Followers: 1

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

GMAT Tests User
 [#permalink] New post 17 Nov 2006, 13:30
B - 5

4C2 + 4 = 10 Not enough

5C2 + 5 = 15 Enough
Intern
Intern
avatar
Joined: 14 Nov 2006
Posts: 15
Followers: 0

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

 [#permalink] New post 17 Nov 2006, 14:03
Sorry guys, but how do you calculate 4C2 or 5C2?
VP
VP
User avatar
Joined: 25 Jun 2006
Posts: 1176
Followers: 2

Kudos [?]: 31 [0], given: 0

GMAT Tests User
 [#permalink] New post 19 Nov 2006, 17:40
B 2.

the equation you get is:

x + xC2 >= 12.

then plug in from the smallest number.

order does not matter because it has to be ordered in alphabetical order, so it is just like combination instead of permutation.
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5097
Location: Singapore
Followers: 16

Kudos [?]: 130 [0], given: 0

GMAT Tests User
 [#permalink] New post 19 Nov 2006, 18:52
A
B
AB
C
BC
AC
D
AD
BD
CD
E

So 5 letters needed
Manager
Manager
avatar
Joined: 10 Sep 2012
Posts: 151
Followers: 2

Kudos [?]: 26 [0], given: 17

Re: [#permalink] New post 15 Dec 2012, 09:22
ywilfred wrote:
A
B
AB
C
BC
AC
D
AD
BD
CD
E

So 5 letters needed



This question is pissing me off because its not designed well...


"or a pair of distinct letters written in alphabetical order."


That clearly means that AD, AC, cannot be used.... these are not in alphabetical order.

I got 7.

A, B, C, D, E, F, G, AB, BC, CD, DE, EF


Obviously the official answer is 5 but can someone please explain to me whe

"a pair of distinct letters written in alphabetical order" is not nullifying AC or AD.... AC is not in alphabetical order.
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18514
Followers: 3195

Kudos [?]: 21365 [0], given: 2546

Re: Re: [#permalink] New post 16 Dec 2012, 22:53
Expert's post
anon1 wrote:
ywilfred wrote:
A
B
AB
C
BC
AC
D
AD
BD
CD
E

So 5 letters needed



This question is pissing me off because its not designed well...


"or a pair of distinct letters written in alphabetical order."


That clearly means that AD, AC, cannot be used.... these are not in alphabetical order.

I got 7.

A, B, C, D, E, F, G, AB, BC, CD, DE, EF


Obviously the official answer is 5 but can someone please explain to me whe

"a pair of distinct letters written in alphabetical order" is not nullifying AC or AD.... AC is not in alphabetical order.


AD is in alphabetical order, DA is not.
AC is in alphabetical order, CA is not.

OPEN DISCUSSION OF THIS QUESTION IS HERE: a-researcher-plans-to-identify-each-participant-in-a-certain-134584.html
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

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; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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. ,11 Mixed Questions, 12 Fresh Meat

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., 11 New DS set.


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

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Re: Re:   [#permalink] 16 Dec 2012, 22:53
    Similar topics Author Replies Last post
Similar
Topics:
17 Experts publish their posts in the topic A researcher plans to identify each participant in a certain sarb 36 17 Jun 2012, 03:13
A researcher palns to identify each participant in a certain puma 3 10 May 2008, 22:36
Each participant in a certain study was assigned a sequence dinesh8 9 06 May 2006, 05:01
Q2: A researcher plans to identify each participant in a nakib77 4 22 Oct 2005, 04:53
2 Experts publish their posts in the topic A researcher plans to identify each participant in a certain saurya_s 5 05 Apr 2005, 14:17
Display posts from previous: Sort by

A researcher plans to identify each participant in a certain

  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®.