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

It is currently 19 Apr 2014, 22:34

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

What is the average (arithmetic mean) of eleven consecutive

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
User avatar
Joined: 21 Sep 2006
Posts: 112
Location: Where you mind is
Followers: 1

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

What is the average (arithmetic mean) of eleven consecutive [#permalink] New post 23 Dec 2007, 23:16
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

0% (00:00) correct 100% (00:18) wrong based on 2 sessions
What is the average (arithmetic mean) of eleven consecutive integers?

(1) The average of the first nine integers is 7

(2) The average of the last nine integers is 9

Scroll down for OA.









OA is D.
Manager
Manager
Joined: 15 Mar 2009
Posts: 147
Concentration: Finance, Entrepreneurship
Schools: UCLA (Anderson) - Class of 2014
GMAT 1: 710 Q49 V35
Followers: 2

Kudos [?]: 11 [0], given: 51

Re: Number Properties (DS) [#permalink] New post 04 Apr 2011, 21:22
LM wrote:
Hang Tuah wrote:
What is the average (arithmetic mean) of eleven consecutive integers?

(1) The average of the first nine integers is 7

(2) The average of the last nine integers is 9

Scroll down for OA.


From ( i ) you can find the 9th integer

Sum = average*9

sum= n*(n+1)/2

then you can solve.

Second does not help

Should be "A".








OA is D.


Should be D.

For (B):
The average of last 9 numbers: (n+2+n+10)/2=9 --> n=3 --> the range is 3, 4 ...13.
SVP
SVP
Joined: 16 Nov 2010
Posts: 1698
Location: United States (IN)
Concentration: Strategy, Technology
Followers: 29

Kudos [?]: 264 [0], given: 36

GMAT Tests User Premium Member Reviews Badge
Re: Number Properties (DS) [#permalink] New post 04 Apr 2011, 22:37
S1-9 = 9 * 7 = 63 = n + n + 1 + n + 2.. n + 8

=> 9n + (1+8)/2 * 8 = 63

=>9n + 36 = 63

=> 9n = 27 => n = 3, and the rest can be calculated.

S2-11 = 9 * 9 = 81 => n+2 + ..... + n+10

9n + (2+10)/2 * 9 = 81

=>9n + 54 = 81

=> 9n = 27 => n = 3, and the rest can be calculated.

Answer - D
_________________

Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)

Director
Director
Joined: 01 Feb 2011
Posts: 773
Followers: 12

Kudos [?]: 76 [0], given: 42

GMAT Tests User
Re: Number Properties (DS) [#permalink] New post 05 Apr 2011, 06:47
Answer is D.

Posted from my mobile device Image
Re: Number Properties (DS)   [#permalink] 05 Apr 2011, 06:47
    Similar topics Author Replies Last post
Similar
Topics:
New posts What is the average of eleven consecutive integers? 1) MBAHopeful 5 25 Dec 2005, 19:24
Popular new posts What is the average of eleven consecutive integers? 1) lhotseface 13 26 Mar 2006, 21:44
New posts What is the average (arithmetic mean) of eleven consecutive faifai0714 6 04 Apr 2007, 23:36
New posts 3 Experts publish their posts in the topic What is the average (arithmetic mean) of eleven consecutive netcaesar 3 25 Jan 2008, 10:44
New posts 11 Experts publish their posts in the topic What is the average (arithmetic mean) of eleven consecutive zz0vlb 6 23 Apr 2010, 17:05
Display posts from previous: Sort by

What is the average (arithmetic mean) of eleven consecutive

  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®.