Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 28 Aug 2012
Posts: 46
Concentration: Operations, Marketing
GPA: 4
WE: Information Technology (Other)

The average (arithmetic mean) monthly income of four workers
[#permalink]
Show Tags
Updated on: 26 Feb 2013, 02:37
Question Stats:
69% (01:34) correct 31% (01:48) wrong based on 182 sessions
HideShow timer Statistics
The average (arithmetic mean) monthly income of four workers is $2,200. After one worker’s income increases by 25 percent the new average income is $2,400. What was the original income of the worker whose monthly income increased? A. $800 B. $1,200 C. $2,400 D. $3,200 E. It cannot be determined from the information given .
Official Answer and Stats are available only to registered users. Register/ Login.
Originally posted by thinktank on 25 Feb 2013, 10:09.
Last edited by Bunuel on 26 Feb 2013, 02:37, edited 2 times in total.
Edited the question.



Verbal Forum Moderator
Joined: 10 Oct 2012
Posts: 583

Re: The average (arithmetic mean) monthly income of four worker
[#permalink]
Show Tags
25 Feb 2013, 10:54
Let the income of the 3 workers which doesn't change be x1,x2,x3. Let the income s increase by 25%. Thus, Initially, x1+x2+x3+s= 8800 And later, x1+x2+x3+1.25s = 9600 Subtracting both of them, 0.25s = 800 Thus, s = 3200. D.
_________________



Senior Manager
Joined: 23 Oct 2010
Posts: 318
Location: Azerbaijan
Concentration: Finance

Re: The average (arithmetic mean) monthly income of four worker
[#permalink]
Show Tags
25 Feb 2013, 10:56
a+b+c+d=4*2.2 => b+c+d=4*2.2a 1.25a+b+c+d=4*2.4 1.25a+ (4*2.2a)=4*2.4 0.25a=4*(2.42.2) (1/4)a=4*.02 a=3.2 ans is D
_________________
Happy are those who dream dreams and are ready to pay the price to make them come true
I am still on all gmat forums. msg me if you want to ask me smth



Math Expert
Joined: 02 Sep 2009
Posts: 59588

Re: The average (arithmetic mean) monthly income of four workers
[#permalink]
Show Tags
26 Feb 2013, 02:44
thinktank wrote: The average (arithmetic mean) monthly income of four workers is $2,200. After one worker’s income increases by 25 percent the new average income is $2,400. What was the original income of the worker whose monthly income increased?
A. $800 B. $1,200 C. $2,400 D. $3,200 E. It cannot be determined from the information given . Increase in total income was 200*4=$800, we know that this increase was 25% (1/4th) of the workers original income, thus his/her original income was 800*4=$3,200. Answer: D. Hope it's clear.
_________________



Intern
Joined: 02 Feb 2014
Posts: 36
Concentration: Finance, General Management
GPA: 3.5

The average (arithmetic mean) monthly income of four workers
[#permalink]
Show Tags
14 Sep 2015, 03:33
Hello. When the question refers to the "original income", it means before the increase of 25% or just the 100% after the increase? Why the question couldn't be like "What is the actual income of the worker who's income increased?" or something like that? The question is correct, I thought that the monthly salary would be an integer and not something like 1886.67. So the original is 3200 and the increase would take it to 4000. All clear! Best!
_________________
"The stock market is filled with individuals who know the price of everything, but the value of nothing."  Philip Fisher



CEO
Joined: 20 Mar 2014
Posts: 2561
Concentration: Finance, Strategy
GPA: 3.7
WE: Engineering (Aerospace and Defense)

Re: The average (arithmetic mean) monthly income of four workers
[#permalink]
Show Tags
14 Sep 2015, 04:39
snfuenza wrote: Hello.
When the question refers to the "original income", it means before the increase of 25% or just the 100% after the increase? Why the question couldn't be like "What is the actual income of the worker who's income increased?" or something like that?
The question is correct, I thought that the monthly salary would be an integer and not something like 1886.67. So the original is 3200 and the increase would take it to 4000. All clear!
Best! What do you mean by your text in red above? The question is clear as stated. Lets say the worker was earning 100$ before the 25% increase. With 25% increase, his new salary will be come = 125$. Thus when I ask you the "original salary" it will always mean that I want you to say 100$ and not 125$.



Intern
Joined: 02 Feb 2014
Posts: 36
Concentration: Finance, General Management
GPA: 3.5

Re: The average (arithmetic mean) monthly income of four workers
[#permalink]
Show Tags
14 Sep 2015, 10:07
Engr2012 wrote: snfuenza wrote: Hello.
When the question refers to the "original income", it means before the increase of 25% or just the 100% after the increase? Why the question couldn't be like "What is the actual income of the worker who's income increased?" or something like that?
The question is correct, I thought that the monthly salary would be an integer and not something like 1886.67. So the original is 3200 and the increase would take it to 4000. All clear!
Best! What do you mean by your text in red above? The question is clear as stated. Lets say the worker was earning 100$ before the 25% increase. With 25% increase, his new salary will be come = 125$. Thus when I ask you the "original salary" it will always mean that I want you to say 100$ and not 125$. Sorry, yes, I got confused and now I understand it. Thanks!
_________________
"The stock market is filled with individuals who know the price of everything, but the value of nothing."  Philip Fisher



Current Student
Joined: 12 Aug 2015
Posts: 2549

Re: The average (arithmetic mean) monthly income of four workers
[#permalink]
Show Tags
10 Dec 2016, 09:09
Great Question. Two methods to solve this one. Method 1> Sum (1) => 8800 Sum(2)=>9600 Increase => 800 Hence 25 percent of income =800 So the original income must be 3200
Method 2> Lets use fundamentals here. Mean 1=> 2200 Mean 2=> 2400 Added su => 200*4=> 800 Hence the increased amount will be 800. So 25 percent of the income will be 800 Hence 100 percent of the income => 800*4=> 3200
Hence D
_________________



Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4834
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)

Re: The average (arithmetic mean) monthly income of four workers
[#permalink]
Show Tags
10 Dec 2016, 11:31
thinktank wrote: The average (arithmetic mean) monthly income of four workers is $2,200. After one worker’s income increases by 25 percent the new average income is $2,400. What was the original income of the worker whose monthly income increased?
A. $800 B. $1,200 C. $2,400 D. $3,200 E. It cannot be determined from the information given . Total salary of 4 workers is 8800 So, a + b + c + d = 8800 Total salary of 4 workers ( after 25% increase in salary of a worker ) is 9600 So, a + a/4 + ( b + c + d ) = 9600 Or, a + a/4 + ( 8800  a ) = 9600 Or, 4a + a + 35200  4a = 38400 Or, a + 35200 = 38400 Or, a = 3200 Hence, correct answer will be (D) 3200
_________________



NonHuman User
Joined: 09 Sep 2013
Posts: 13723

Re: The average (arithmetic mean) monthly income of four workers
[#permalink]
Show Tags
24 Mar 2019, 18:15
Hello from the GMAT Club BumpBot! Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up  doing my job. I think you may find it valuable (esp those replies with Kudos). Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________




Re: The average (arithmetic mean) monthly income of four workers
[#permalink]
24 Mar 2019, 18:15






