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Register now and save up to $200 Available with Beat the GMAT members only code • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE Available with Beat the GMAT members only code ## salary of the 10 employees This topic has 5 expert replies and 6 member replies ### GMAT/MBA Expert sanju09 GMAT Instructor Joined 21 Jan 2009 Posted: 3650 messages Followed by: 81 members Upvotes: 267 GMAT Score: 760 #### salary of the 10 employees Mon Mar 12, 2012 2:49 am Last year the average (arithmetic mean) salary of the 10 employees of Company X was$42,800. What is the average (arithmetic mean) 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.

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

www.manyagroup.com

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killer1387 Legendary Member
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Wed Mar 14, 2012 3:08 am
sanju09 wrote:
Last year the average (arithmetic mean) salary of the 10 employees of Company X was $42,800. What is the average (arithmetic mean) 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 b1, b2...b10 given: 42800 = (b1+b2+..+b10)/10 => b1+b2..+b8 = (428000)-(b9+b10) statement 1: also given: b1(year2) = 1.15b1..similarly till b8 1.15b1+1.15b2.....1.15b8 = (b1...b8)+0.15(b1...b8) insufficient statement 2: b9, b10 is same insufficient 1+2 (b1+b2...+b8)+b9+b10 + 0.15(b1...+b8)/10 0.15(b1...+b8) cant be determined Insufficient Hence E. @sanju09 please point out what i am missing here. No offence but still i am not convinced by the distribution you provided. How can this part "0.15(b1...+b8)" be determined by the information available? thnx ### GMAT/MBA Expert GMATGuruNY GMAT Instructor Joined 25 May 2010 Posted: 14042 messages Followed by: 1813 members Upvotes: 13060 GMAT Score: 790 Wed Mar 14, 2012 7:39 am sanju09 wrote: Last year the average (arithmetic mean) salary of the 10 employees of Company X was$42,800. What is the average (arithmetic mean) 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.

Sum of the salaries last year = number*average = (10)(42,800) = 428,000.

Statements 1 and 2 combined:

Case 1: The 8 employees in statement 1 each earned $50,000 last year Sum of their salaries last year = 8(50,000) = 400,000. New sum this year = 1.15(400,000) = 460,000. Sum of the salaries of the other 2 employees last year and this year = 428,000-400,000 = 28,000. Average this year = (460,000+28,000)/10 = 48,800. Case 2: The 8 employees in statement 1 each earned$1000 last year
Sum of their salaries last year = 8(1,000) = 8,000.
New sum this year = 1.15(8,000) = 9200.
Sum of the salaries of the other 2 employees last year and this year = 428,000-8,000 = 420,000.
Average this year = (9200+420,000)/10 = 42,920.

Since different averages this year are possible, INSUFFICIENT.

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killer1387 Legendary Member
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Mon Mar 12, 2012 6:18 am
IMO E

amit.trivedi@ymail.com Legendary Member
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Tue Mar 13, 2012 3:31 am
Last year the average (arithmetic mean) salary of the 10 employees of Company X was $42,800. What is the average (arithmetic mean) 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. Even my answer turns out to be E. Statement 1: You know the average salary of all the 10 people of last year as$42800.

So you max you can come to know after all this is the total salary of the 10 people as $428000. You do not know each one's salary so you cannot increase each by 15% and then find the average. Also you do not know the minimum salary and the median salary or something like that to know the limits. Neither do you know from statement 1 that the salary of the other 2 people whether increased or decreased or remained the same or if increase then by what % and if decrease then by what %. Hence statement 1 insufficient... Statement 2: Same as above. Alone insufficient... Combined 1 and 2: when you combine the statements all you can find is that the average salary for this year is between$42800 and 49220.

I got this by adding 15% increase of all the 10 people...

But other than that we clearly cannot find out as we do not know any limits of the salary of each person....

Hence E is the correct answer...

Hope i am right man...

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sanju09 GMAT Instructor
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Wed Mar 14, 2012 1:18 am
Total salary of the 10 employees = $42,800 X 10 =$4, 28,000.

I. This statement means that 8 out of 10 employees are getting 15 percent more than $42,800 this year, or the total salary of those 8 employees is$42,800 X 8 X 1.15. in order to find the average salary of the same 10 employees this year, we need to know the total salary of the remaining 2 employees this year, which is not given. Insufficient

II. This statement means that 2 out of 10 employees are getting the same $42,800 each, this year too, hence this year‘s total salary of those 2 employees is$42,800 X 2. We need to know the total salary of the remaining 8 employees this year, which is not given. Insufficient

Taking I and II together, we can realize that the 8 employees mentioned in statement I have nothing to do with the 2 employees mentioned in statement II. Hence, total salary of the same 10 employees this year can be taken equal to $42,800 X 8 X 1.15 +$42,800 X 2 to answer the average (arithmetic mean) salary. Sufficient

OA C

_________________
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

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killer1387 Legendary Member
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Wed Mar 14, 2012 1:28 am
sanju09 wrote:
Total salary of the 10 employees = $42,800 X 10 =$4, 28,000.

I. This statement means that 8 out of 10 employees are getting 15 percent more than $42,800 this year, or the total salary of those 8 employees is$42,800 X 8 X 1.15. in order to find the average salary of the same 10 employees this year, we need to know the total salary of the remaining 2 employees this year, which is not given. Insufficient

II. This statement means that 2 out of 10 employees are getting the same $42,800 each, this year too, hence this year‘s total salary of those 2 employees is$42,800 X 2. We need to know the total salary of the remaining 8 employees this year, which is not given. Insufficient

Taking I and II together, we can realize that the 8 employees mentioned in statement I have nothing to do with the 2 employees mentioned in statement II. Hence, total salary of the same 10 employees this year can be taken equal to $42,800 X 8 X 1.15 +$42,800 X 2 to answer the average (arithmetic mean) salary. Sufficient

OA C
please elaborate on the part in bold.

I think its not possible to calculate from both 1 and 2

this yr's salary= 1.15 (a+b+c+d+e+f+g+h)+(i+j)

we only have a+b+c.....+j=428000

pls explain

### GMAT/MBA Expert

sanju09 GMAT Instructor
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Wed Mar 14, 2012 1:41 am
killer1387 wrote:
sanju09 wrote:
Total salary of the 10 employees = $42,800 X 10 =$4, 28,000.

I. This statement means that 8 out of 10 employees are getting 15 percent more than $42,800 this year, or the total salary of those 8 employees is$42,800 X 8 X 1.15. in order to find the average salary of the same 10 employees this year, we need to know the total salary of the remaining 2 employees this year, which is not given. Insufficient

II. This statement means that 2 out of 10 employees are getting the same $42,800 each, this year too, hence this year‘s total salary of those 2 employees is$42,800 X 2. We need to know the total salary of the remaining 8 employees this year, which is not given. Insufficient

Taking I and II together, we can realize that the 8 employees mentioned in statement I have nothing to do with the 2 employees mentioned in statement II. Hence, total salary of the same 10 employees this year can be taken equal to $42,800 X 8 X 1.15 +$42,800 X 2 to answer the average (arithmetic mean) salary. Sufficient

OA C
please elaborate on the part in bold.

I think its not possible to calculate from both 1 and 2

this yr's salary= 1.15 (a+b+c+d+e+f+g+h)+(i+j)

we only have a+b+c.....+j=428000

pls explain
Please read what's in bold in my explanation above. If you agree, then (a + b + c + d + e + f + g + h) are all different from (i + j). The conclusion from stem "Total salary of the 10 employees = $42,800 X 10 =$4, 28,000." is not playing any role here.

_________________
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

Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.
killer1387 Legendary Member
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Wed Mar 14, 2012 1:48 am
sanju09 wrote:
killer1387 wrote:
sanju09 wrote:
Total salary of the 10 employees = $42,800 X 10 =$4, 28,000.

I. This statement means that 8 out of 10 employees are getting 15 percent more than $42,800 this year, or the total salary of those 8 employees is$42,800 X 8 X 1.15. in order to find the average salary of the same 10 employees this year, we need to know the total salary of the remaining 2 employees this year, which is not given. Insufficient

II. This statement means that 2 out of 10 employees are getting the same $42,800 each, this year too, hence this year‘s total salary of those 2 employees is$42,800 X 2. We need to know the total salary of the remaining 8 employees this year, which is not given. Insufficient

Taking I and II together, we can realize that the 8 employees mentioned in statement I have nothing to do with the 2 employees mentioned in statement II. Hence, total salary of the same 10 employees this year can be taken equal to $42,800 X 8 X 1.15 +$42,800 X 2 to answer the average (arithmetic mean) salary. Sufficient

OA C
please elaborate on the part in bold.

I think its not possible to calculate from both 1 and 2

this yr's salary= 1.15 (a+b+c+d+e+f+g+h)+(i+j)

we only have a+b+c.....+j=428000

pls explain
Please read what's in bold in my explanation above. If you agree, then (a + b + c + d + e + f + g + h) are all different from (i + j). The conclusion from stem "Total salary of the 10 employees = $42,800 X 10 =$4, 28,000." is not playing any role here.
That is ok i understand that but does this information makes us able to calculate the whole this year salary because we still dont know the break up of the grp of 8 and 2 people separately,

how can we reach this step: $42,800 X 8 X 1.15 +$42,800 X 2--> this means the average has been uniformly distributed among the 8 and 2 employees, which is not correct as no information states that in the question.

If possible could you please provide the procedure used to calculate this year salary from those two statements.

thnx

### GMAT/MBA Expert

sanju09 GMAT Instructor
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Wed Mar 14, 2012 2:02 am
Oh dear…my dear…

Neither statement is talking about the average salary. Read the statements carefully and mind what “For 8 of the 10 employees” or “For 2 of the 10 employees” translate to. For your information, it translates to “each of 8” or “each of 2” mentioned respectively. Hence by multiplying new salary with the number of employees in each case, I am definitely not trying to distribute the average over number.

_________________
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

Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.

### GMAT/MBA Expert

sanju09 GMAT Instructor
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Fri Mar 16, 2012 12:49 am
killer1387 wrote:
sanju09 wrote:
Last year the average (arithmetic mean) salary of the 10 employees of Company X was $42,800. What is the average (arithmetic mean) 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 b1, b2...b10 given: 42800 = (b1+b2+..+b10)/10 => b1+b2..+b8 = (428000)-(b9+b10) statement 1: also given: b1(year2) = 1.15b1..similarly till b8 1.15b1+1.15b2.....1.15b8 = (b1...b8)+0.15(b1...b8) insufficient statement 2: b9, b10 is same insufficient 1+2 (b1+b2...+b8)+b9+b10 + 0.15(b1...+b8)/10 0.15(b1...+b8) cant be determined Insufficient Hence E. @sanju09 please point out what i am missing here. No offence but still i am not convinced by the distribution you provided. How can this part "0.15(b1...+b8)" be determined by the information available? thnx Oh you are correct! The correct answer must be E; source is some GMAT Prep and the OA provided is definitely wrong. _________________ 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 Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now. voodoo_child Master | Next Rank: 500 Posts Joined 10 Feb 2011 Posted: 404 messages Followed by: 1 members Upvotes: 3 Mon Mar 19, 2012 8:58 am GMATGuruNY wrote: sanju09 wrote: Last year the average (arithmetic mean) salary of the 10 employees of Company X was$42,800. What is the average (arithmetic mean) 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.

Sum of the salaries last year = number*average = (10)(42,800) = 428,000.

Statements 1 and 2 combined:

Case 1: The 8 employees in statement 1 each earned $50,000 last year Sum of their salaries last year = 8(50,000) = 400,000. New sum this year = 1.15(400,000) = 460,000. Sum of the salaries of the other 2 employees last year and this year = 428,000-400,000 = 28,000. Average this year = (460,000+28,000)/10 = 48,800. Case 2: The 8 employees in statement 1 each earned$1000 last year
Sum of their salaries last year = 8(1,000) = 8,000.
New sum this year = 1.15(8,000) = 9200.
Sum of the salaries of the other 2 employees last year and this year = 428,000-8,000 = 420,000.
Average this year = (9200+420,000)/10 = 42,920.

Since different averages this year are possible, INSUFFICIENT.

Mitch,
why did you assume, in case b, that the salary of the other 8 people changed? It could be possible that the mean did not change at all this year. In other words, salary didn't change for two poeple and the other 8 guys. Correct? The question doesn't state that the mean has to change.

Thanks

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