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

It is currently 10 Jul 2014, 16:10

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

Last year the average (arithmetic mean) salary of the 10

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 13 Dec 2005
Posts: 64
Followers: 1

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

Last year the average (arithmetic mean) salary of the 10 [#permalink] New post 02 Dec 2006, 07:07
00:00
A
B
C
D
E

Difficulty:

  25% (low)

Question Stats:

70% (01:28) correct 29% (00:46) wrong based on 51 sessions
Last year the average (arithmetic mean) salary of the 10 employees of Company X was $42,800. What is the average salary of the same 10 employees this year?

1) For 8 of the 10 employees, this year's salary is 15 percent greater than last year's salary.
2) For 2 of the 10 employees, this year's salary is the same as last year's salary.

Official Guide 12 Question

GMAT Official Guide 12

Question: 46
Page: 26
Difficulty: 700

Find All Official Guide Questions

Video Explanations:
[Reveal] Spoiler: OA
Kaplan Promo CodeKnewton GMAT Discount CodesVeritas Prep GMAT Discount Codes
Senior Manager
Senior Manager
avatar
Joined: 20 Feb 2006
Posts: 375
Followers: 1

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

GMAT Tests User
 [#permalink] New post 02 Dec 2006, 07:21
E for me

From 1) Depending on which two employees didn't get 15% increase would affect the overall total. Eg if top two salaries didn't get the 15% increase then it would yield a lower total and hence average than if the bottom two salaries didn't get a 15% increase. INSUFF

From 2) This tells us even less than 1). What % change in salary did others get? Which two salaries didn't get increase? INSUFF

Together,
Still dont know which two employees didn't get increase and the respective salaries of the others.
Director
Director
User avatar
Affiliations: FRM Charter holder
Joined: 02 Dec 2006
Posts: 736
Schools: Stanford, Chicago Booth, Babson College
Followers: 5

Kudos [?]: 15 [0], given: 4

GMAT Tests User
 [#permalink] New post 02 Dec 2006, 07:21
Straight E.

If they were to mention in the second statement that, these 2 are excluding those 8, then something is possible.
Manager
Manager
avatar
Joined: 13 Dec 2005
Posts: 64
Followers: 1

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

Explanation? [#permalink] New post 02 Dec 2006, 07:23
Can you please explain why? From statement 1 wouldn't you know that for 8 of the 10 employees, the salary is now $49,220 (42,800 * 1.15)...and from statement 2 you would know that the salary of the remaining 2 is (still) 42,800? Thus you could do:

(49220*8) + (42800*2)
--------------------------- = average salary
10

..and thus the answer would be C. How is that wrong?
Senior Manager
Senior Manager
avatar
Joined: 20 Feb 2006
Posts: 375
Followers: 1

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

GMAT Tests User
 [#permalink] New post 02 Dec 2006, 07:27
aurobindo wrote:
Straight E.

If they were to mention in the second statement that, these 2 are excluding those 8, then something is possible.


It still wouldn't help - taking both together we know that 8 got 15% increase but 2 got no increase (or loss). However, we'd still need to know where in the range of salaries those two employees were.

Eg.
Take a set of numbers 2,3,5,6 Mean = 4

If you double the lowest 3 numbers you get 4,6,10,6 Mean = 6.5
If you double the highest 3 numbers you get 2,6,10,12 Mean = 7.5

So simply knowing that x number of employees got/didn't get an increase doesn't help
Director
Director
avatar
Joined: 28 Dec 2005
Posts: 922
Followers: 2

Kudos [?]: 37 [0], given: 0

GMAT Tests User
 [#permalink] New post 02 Dec 2006, 07:30
Last year the average (arithmetic mean) salary of the 10 employees of Company X was $42,800. What is the average salary of the same 10 employees this year?

1) For 8 of the 10 employees, this year's salary is 15 percent greater than last year's salary.

2) For 2 of the 10 employees, this year's salary is the same as last year's salary.

Let the salaries of the 10 be a1, a2...a10

given: 42800 = (a1+a2+..+a10)/10 => sum(a1...+a10) = 428000
also: a1+a2..a8 = (42800)-(a9+a10)

also given: a1(year2) = 1.15a1..similarly till a8

1.15a1+1.15a2.....1.15a8 = (a1...a8)+0.15(a1...a8)

from 2:

a9, a10 is same

combining
(a1+a2...a8)+a9+a10 + 0.15(a1...a8)/10

still cannot be determined. So E
Manager
Manager
avatar
Joined: 08 Oct 2009
Posts: 64
Location: Denver, CO
WE 1: IT Business Analyst-Building Materials Industry
Followers: 1

Kudos [?]: 11 [0], given: 4

Re: OG Data Sufficiency average problem [#permalink] New post 19 Apr 2010, 18:15
I'm really sorry to bump such an old thread but qant to play devil's advocate with this question.
If statement 2 stated that the lowest two salaries of the ten employees stayed the same, then the both of the statements together would be sufficient correct?

The average of the salaries would be ((42800*2)+(1.15*42800*8))/10= 47936
Senior Manager
Senior Manager
User avatar
Joined: 01 Apr 2010
Posts: 300
Location: Kuwait
Schools: Sloan '16 (M)
GMAT 1: 710 Q49 V37
GPA: 3.2
WE: Information Technology (Consulting)
Followers: 4

Kudos [?]: 54 [0], given: 11

GMAT Tests User
Re: OG Data Sufficiency average problem [#permalink] New post 20 Apr 2010, 12:26
You have no information on what the lowest 2 salaries were, just that the average was 42,800. What you assumed was the extra information tells us that the two lowest salaries stayed the same is not equivalent to they were the average values.
Re: OG Data Sufficiency average problem   [#permalink] 20 Apr 2010, 12:26
    Similar topics Author Replies Last post
Similar
Topics:
6 Experts publish their posts in the topic Last year the average (arithmetic mean) salary of the 10 Bunuel 6 16 Jul 2012, 03:51
Experts publish their posts in the topic Last year the average (arithmetic mean) salary of the 10 Latinapp 6 05 Feb 2012, 08:58
2 At State University, the average (arithmetic mean) salary of rxs0005 8 21 Nov 2010, 07:19
The arithmetic mean (average) of a set of 10 numbers is 10. coldweather999 16 26 Sep 2007, 07:07
Last year the average (arithmetic mean) salary of 10 buckkitty 2 19 Feb 2006, 15:40
Display posts from previous: Sort by

Last year the average (arithmetic mean) salary of the 10

  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®.