It is currently 25 Feb 2018, 05:48

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

An automated manufacturing unit employs N experts such that the range

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Expert Post
1 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43901
An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 07 Apr 2015, 05:34
1
This post received
KUDOS
Expert's post
19
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

43% (02:12) correct 57% (02:38) wrong based on 189 sessions

HideShow timer Statistics

An automated manufacturing unit employs N experts such that the range of their monthly salaries is $10,000. Their average monthly salary is $7000 above the lowest salary while the median monthly salary is only $5000 above the lowest salary. What is the minimum value of N?

(A) 10
(B) 12
(C) 14
(D) 15
(E) 20

Kudos for a correct solution.
[Reveal] Spoiler: OA

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

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?
Extra-hard Quant Tests with Brilliant Analytics

Intern
Intern
avatar
Joined: 21 Sep 2013
Posts: 28
Location: United States
Concentration: Finance, General Management
GMAT Date: 10-25-2013
GPA: 3
WE: Operations (Mutual Funds and Brokerage)
An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 07 Apr 2015, 10:15
Bunuel wrote:
An automated manufacturing unit employs N experts such that the range of their monthly salaries is $10,000. Their average monthly salary is $7000 above the lowest salary while the median monthly salary is only $5000 above the lowest salary. What is the minimum value of N?

(A) 10
(B) 12
(C) 14
(D) 15
(E) 20

Kudos for a correct solution.



let s take lowest salary to be 1000.
therefore highest is 11000 ( because range = highest - lowest).
median is 6000.(lowest +5000)


now we need to minimize N and we know that avg is(1000+7000) 8000, which is above the median (6000).
to get the mean to 8000 we ll have to maxmize the salaries of the ppl above the mean. but max we can take is 11000.
at the same time maximize salaries of people below the median therefore , max we can take is 6000.
now we have values of 3(1000+6000+11000) people which totals 18000. thus avg is 6000 as of now .
now we ll start adding 2 ppl at a time , one with sal above the mean and one with below. therefore 6000+11000=17000
so now for 5 people the avg is (17000+18000)/5=7000. so this way we see the avg is moving up towards 8000. similarly we keep adding 2 ppl and by the time we cross 15 ppl the avg crosses 8000.
hence IMO the ans is D.

Last edited by Yash12345 on 13 Apr 2015, 06:19, edited 1 time in total.
1 KUDOS received
Manager
Manager
avatar
Joined: 17 Mar 2015
Posts: 121
An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 08 Apr 2015, 03:19
1
This post received
KUDOS
Am - minimum salary, Am + 10000 = max salary, Am + 5000 - median, Am + 7000 - average
What the guy above said is indeed correct regarding the way to approach our goal. Median must be constant, so we need to add people accordingly, as in one person "to the left" from median and 1 person "to the right" from the average, to offset the first person's salary. With just 2 people we got average at Am + 5,5 so we need to get that 1,5 somewhere to match Am+7000. The quickest way to increase our average is to pick the biggest possible salaries for the new people, thus using information from our question I came up with this equation.
\(A_m+7000=\frac{(A_m+a*(A_m+5000)+(b+1)*(A_m+10000))}{(a+b+2)}\)
a - number of people with salary equal to median
b - number of people with salary equal to max salary
in order to preserve our median's value, \(a >= b + 1\) (coz if we have to many people with max salary, our median will shift upwards)
solving the equation we end up with
\(2a + 4 = 3b\)
taking into account the \(a >=b + 1\) with a simple plug method we determine that a = 7, b = 6 are the first possible values we can use and thus \(a + b + 2 = 15\) - minimum amount of people, the answer to our question.
15 = answer D
Expert Post
1 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43901
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 13 Apr 2015, 06:03
1
This post received
KUDOS
Expert's post
2
This post was
BOOKMARKED
Bunuel wrote:
An automated manufacturing unit employs N experts such that the range of their monthly salaries is $10,000. Their average monthly salary is $7000 above the lowest salary while the median monthly salary is only $5000 above the lowest salary. What is the minimum value of N?

(A) 10
(B) 12
(C) 14
(D) 15
(E) 20

Kudos for a correct solution.


VERITAS PREP OFFICIAL SOLUTION:

Let’s first assimilate the information we have. We need to find the minimum number of experts that must be there. Why should there be a minimum number of people satisfying these statistics? Let’s try to understand that with some numbers.

Say, N cannot be 1 i.e. there cannot be a single expert in the unit because then you cannot have the range of $10,000. You need at least two people to have a range – the difference of their salaries would be the range in that case.

So there are at least 2 people – say one with salary 0 and the other with 10,000. No salary will lie outside this range.

Median is $5000 – i.e. when all salaries are listed in increasing order, the middle salary (or average of middle two) is $5000. With 2 people, one at 0 and the other at 10,000, the median will be the average of the two i.e. (0 + 10,000)/2 = $5000. Since there are at least 10 people, there is probably someone earning $5000. Let’s put in 5000 there for reference.

0 … 5000 … 10,000
Arithmetic mean of all the salaries is $7000. Now, mean of 0, 5000 and 10,000 is $5000, not $7000 so this means that we need to add some more people. We need to add them more toward 10,000 than toward 0 to get a higher mean. So we will try to get a mean of $7000.

Let’s use deviations from the mean method to find where we need to add more people.

0 is 7000 less than 7000 and 5000 is 2000 less than 7000 which means we have a total of $9000 less than 7000. On the other hand, 10,000 is 3000 more than 7000. The deviations on the two sides of mean do not balance out. To balance, we need to add two more people at a salary of $10,000 so that the total deviation on the right of 7000 is also $9000. Note that since we need the minimum number of experts, we should add new people at 10,000 so that they quickly make up the deficit in the deviation. If we add them at 8000 or 9000 etc, we will need to add more people to make up the deficit at the right.

Now we have
0 … 5000 … 10000, 10000, 10000

Now the mean is 7000 but note that the median has gone awry. It is 10,000 now instead of the 5000 that is required. So we will need to add more people at 5000 to bring the median back to 5000. But that will disturb our mean again! So when we add some people at 5000, we will need to add some at 10,000 too to keep the mean at 7000.

5000 is 2000 less than 7000 and 10,000 is 3000 more than 7000. We don’t want to disturb the total deviation from 7000. So every time we add 3 people at 5000 (which will be a total deviation of 6000 less than 7000), we will need to add 2 people at 10,000 (which will be a total deviation of 6000 more than 7000), to keep the mean at 7000 – this is the most important step. Ensure that you have understood this before moving ahead.

When we add 3 people at 5000 and 2 at 10,000, we are in effect adding an extra person at 5000 and hence it moves our median a bit to the left.

Let’s try one such set of addition:
0 … 5000, 5000, 5000, 5000 … 10000, 10000, 10000, 10000, 10000

The median is not $5000 yet. Let’s try one more set of addition.
0 … 5000, 5000, 5000, 5000, 5000, 5000, 5000 … 10000, 10000, 10000, 10000, 10000, 10000, 10000

The median now is $5000 and we have maintained the mean at $7000.

This gives us a total of 15 people.

Answer (D)

Granted, the question is tough but note that it uses very basic concepts and that is the hallmark of a good GMAT question!
Try to come up with some other methods of solving this.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

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?
Extra-hard Quant Tests with Brilliant Analytics

Senior Manager
Senior Manager
User avatar
G
Joined: 23 Jun 2012
Posts: 344
Location: Pakistan
Concentration: Strategy, International Business
GPA: 3.76
GMAT ToolKit User Reviews Badge
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 08 Feb 2016, 21:33
Okay i need an advise...
the median value is $5000, doesnt this shows that the number of experts must be some Odd number (answer choice D)..?
_________________

Push yourself again and again. Don't give an inch until the final buzzer sounds. -Larry Bird
Success isn't something that just happens - success is learned, success is practiced and then it is shared. -Sparky Anderson
-S

Expert Post
2 KUDOS received
EMPOWERgmat Instructor
User avatar
D
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 11074
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: 340 Q170 V170
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 12 Feb 2016, 17:49
2
This post received
KUDOS
Expert's post
Hi sananoor,

When a set has an EVEN number of values, the median is equal to the AVERAGE of the two 'middle terms.' As such it can still be an integer.

Here are some examples:

{5, 5, 5, 5} --> the median is 5

{4, 6, 8, 9} --> the median is 7

GMAT assassins aren't born, they're made,
Rich
_________________

760+: Learn What GMAT Assassins Do to Score at the Highest Levels
Contact Rich at: Rich.C@empowergmat.com

Rich Cohen

Co-Founder & GMAT Assassin

Special Offer: Save $75 + GMAT Club Tests Free
  Official GMAT Exam Packs + 70 Pt. Improvement Guarantee
www.empowergmat.com/

***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************

Senior Manager
Senior Manager
User avatar
G
Joined: 19 Oct 2012
Posts: 350
Location: India
Concentration: General Management, Operations
GMAT 1: 660 Q47 V35
GMAT 2: 710 Q50 V38
GPA: 3.81
WE: Information Technology (Computer Software)
An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 25 Feb 2016, 22:32
Quote:
Question: An automated manufacturing unit employs N experts. Their average monthly salary is $7000 while the median monthly salary is only $5000. If the range of their monthly salaries is $10,000, what is the minimum value of N?

(A)10
(B)12
(C)14
(D)15
(E)20


Hey Bunuel,
I am quoting a vairation of this question from statistics-made-easy-all-in-one-topic-203966.html#p1563225 and I see why there was a tweak in the verbiage introduced as in this thread (mostly to avoid below). Please validate my solution and confirm if I am thinking in the right direction: :!:

We are given the salary sequence as: ... 5000(median),...,7000(mean),....
I choose $15000 as the higher limit to the salary, so that gives me: ..., 5000,7000,15000
To balance out the mean and satisfy the range condition, I add 5000s on left side of the mean: 5000,5000,5000,5000,7000,15000. (Mean: 7000, Range:10000, Median: 5000).
So the least possible value of N satisfying all conditions is 6. (which is lower than any answer choices mentioned) :P

If above is correct, may be it would be a good idea to edit the question here statistics-made-easy-all-in-one-topic-203966.html#p1563225 to make it more full proof. :)
_________________

Citius, Altius, Fortius

1 KUDOS received
Intern
Intern
avatar
Joined: 25 Apr 2015
Posts: 4
GMAT Date: 10-12-2015
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 15 Mar 2016, 21:06
1
This post received
KUDOS
5000,5000,5000,5000,5000,5000,6000,9000,10000,15000 ( TOTAL 10 NUMBERS )
RANGE= 15000-5000=10000
MEDIAN=(5000+5000)/2 = 5000
AVERAGE= SUM/TOTAL=70000/10=7000
OPTION : A minimum
Retired Moderator
User avatar
P
Joined: 12 Aug 2015
Posts: 2430
GRE 1: 323 Q169 V154
GMAT ToolKit User Premium Member
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 19 Mar 2016, 09:59
MuraliPappala wrote:
5000,5000,5000,5000,5000,5000,6000,9000,10000,15000 ( TOTAL 10 NUMBERS )
RANGE= 15000-5000=10000
MEDIAN=(5000+5000)/2 = 5000
AVERAGE= SUM/TOTAL=70000/10=7000
OPTION : A minimum




Read carefully the question says ABOVE the LOWEST VALUE
i.e in your example the mean has to be 12000 and Median has to be 10000
_________________


Getting into HOLLYWOOD with an MBA

Stone Cold's Mock Tests for GMAT-Quant(700+)

Manager
Manager
avatar
Joined: 24 May 2013
Posts: 85
GMAT ToolKit User
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 20 Mar 2016, 02:28
An automated manufacturing unit employs N experts such that the range of their monthly salaries is $10,000. Their average monthly salary is $7000 above the lowest salary while the median monthly salary is only $5000 above the lowest salary. What is the minimum value of N?

Let the lowest/first no is L.
Max will be 10000+L, Median will be L+5000.
L................L+5000...............L+10000 =====> Mean = (7000+L)

......(N-1)/2 nos....1(i.e. L+5000).........(N-1)/2 Nos..... In total N nos

The nos between L and (L+5000) are assumed to be same as (L+5000) while the numbers between (L+5000) and (L+10000) are assumed to be (10000+L).
I have taken (L+5000) and (L+10000) as the mean is 7000+L which may be achieved only if such values are taken.

Sum = N*Mean
L +{(N-3)/2}*(L+5000) +(L+5000) +{(N-1)/2}*(L+10000) = N*(L+7000)
Solving we get N = 15. Rest all cancels out.


Hence D
Manager
Manager
User avatar
Joined: 27 Apr 2016
Posts: 93
Location: Brazil
GMAT 1: 610 Q37 V36
GPA: 2.7
WE: Information Technology (Education)
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 03 May 2016, 13:04
Hello everyone.

I ended up getting a totally different result: a minimum of 3 experts.

Suppose you have three experts with the salaries of $3000, $5000 and $13000.

Is the median $5000? CHECK
Is the average $7000? $3000 + $5000 + $13000 = $21000 / 3 = $7000 CHECK
Is the range $10000? $13000 - $3000 = $10000 CHECK

I really think the author's answer explanation for this one takes a lot of things for granted. For example, where does the assumption of "at least 10 experts" come from early on? Besides, you do realize that you don't necessarily have to assume the minimum and maximum salaries to be median-range/2 and median+range/2, right? As long as you have one expert earning 5k, an odd number of experts, and the expert's salaries evenly spread between the 5k mark, the median will remain 5k.

So how did I come up with these values? Let's analyse each variable:

A median of 5k means you'll have at least one expert.

A range of 10k means at least two experts. You could have only two experts, one earning 10k and another earning zero, and you would still have a 5k median.

An average of 7k means the sum of the salaries will be a multiple of 7. This also means you will need more than two experts to meet all the criteria, because if you had only 2, you would need to meet the median criteria which means the sum of the two salaries divided by two, AND the average criteria which is, under this context, calculated the same way, but has a different value.

Combining all the three values, you know that you must have at least one expert earning 5k to meet the 5k criteria, but since the range is 10k and you must express that with at least 2 more experts, the sum of the salaries is at least 15k. Noting that the sum of the salaries must also be a multiple of 7, the first number that meets all the conditions is 21k, where the median salary is 5k, the lowest salary could be anything between 0 and 5k, exclusive, and the maximum salary is 21k - 5k - lowest salary.
_________________

The errant cosmos works against me!

Manager
Manager
User avatar
B
Joined: 16 Mar 2016
Posts: 134
Location: France
GMAT 1: 660 Q47 V33
GPA: 3.25
GMAT ToolKit User
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 03 May 2016, 13:45
samirabrahao1 wrote:
Hello everyone.

I ended up getting a totally different result: a minimum of 3 experts.

Suppose you have three experts with the salaries of $3000, $5000 and $13000.

Is the median $5000? CHECK
Is the average $7000? $3000 + $5000 + $13000 = $21000 / 3 = $7000 CHECK
Is the range $10000? $13000 - $3000 = $10000 CHECK

I really think the author's answer explanation for this one takes a lot of things for granted. For example, where does the assumption of "at least 10 experts" come from early on? Besides, you do realize that you don't necessarily have to assume the minimum and maximum salaries to be median-range/2 and median+range/2, right? As long as you have one expert earning 5k, an odd number of experts, and the expert's salaries evenly spread between the 5k mark, the median will remain 5k.

So how did I come up with these values? Let's analyse each variable:

A median of 5k means you'll have at least one expert.

A range of 10k means at least two experts. You could have only two experts, one earning 10k and another earning zero, and you would still have a 5k median.

An average of 7k means the sum of the salaries will be a multiple of 7. This also means you will need more than two experts to meet all the criteria, because if you had only 2, you would need to meet the median criteria which means the sum of the two salaries divided by two, AND the average criteria which is, under this context, calculated the same way, but has a different value.

Combining all the three values, you know that you must have at least one expert earning 5k to meet the 5k criteria, but since the range is 10k and you must express that with at least 2 more experts, the sum of the salaries is at least 15k. Noting that the sum of the salaries must also be a multiple of 7, the first number that meets all the conditions is 21k, where the median salary is 5k, the lowest salary could be anything between 0 and 5k, exclusive, and the maximum salary is 21k - 5k - lowest salary.


Re-read the question : the average is not 7000, but 7000 above the least value ;)
Manager
Manager
User avatar
Joined: 27 Apr 2016
Posts: 93
Location: Brazil
GMAT 1: 610 Q37 V36
GPA: 2.7
WE: Information Technology (Education)
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 03 May 2016, 14:35
Alex75PAris wrote:
Re-read the question : the average is not 7000, but 7000 above the least value ;)


It appears someone has modified the original question, which was:

statistics-made-easy-all-in-one-topic-203966.html#p1563225

"Question: An automated manufacturing unit employs N experts. Their average monthly salary is $7000 while the median monthly salary is only $5000. If the range of their monthly salaries is $10,000, what is the minimum value of N?

(A)10
(B)12
(C)14
(D)15
(E)20"

The discussion link contained in that thread leads to this one, so I assumed this was related to the same question.
_________________

The errant cosmos works against me!

Manager
Manager
User avatar
S
Joined: 20 Mar 2015
Posts: 73
Location: United States
Concentration: General Management, Strategy
WE: Design (Manufacturing)
An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 10 Aug 2016, 09:15
Bunuel wrote:
An automated manufacturing unit employs N experts such that the range of their monthly salaries is $10,000. Their average monthly salary is $7000 above the lowest salary while the median monthly salary is only $5000 above the lowest salary. What is the minimum value of N?

(A) 10
(B) 12
(C) 14
(D) 15
(E) 20

Kudos for a correct solution.

0 5000 5000 5000 5000 5000 9800 9800 9800 9800 9800 10000
Count=12, Average 7000. median=5000 , Hence answer can be 12 as well.
Many options like this can be worked out as this is a complete hit & trial question. I would rate this question as extremely poor w.r.t GMAT standards
Manager
Manager
User avatar
S
Joined: 20 Sep 2016
Posts: 122
GMAT 1: 680 Q49 V35
GPA: 3.99
An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 10 May 2017, 13:19
Hi VeritasPrepKarishma .
Could you check would my reasoning be correct, If the questiion was the original one. I want to check this concept on a similar problem. So here is the old version: An automated manufacturing unit employs N experts. Their average monthly salary is $7000 while the median monthly salary is only $5000. If the range of their monthly salaries is $10,000, what is the minimum value of N? (so there is no condition saying that mean is 7000 above lowest salary)

Here is how I would do it: Start with 3000, 5000, 13000, try to get N>10 and keep mean at 7000 and mode at 5000(If I am right starting with mean 7000 minimizes number of additions needed to be done - I want to contrast this with starting with 0, 5000, 10000).
We want to add the least number of elements possible, so in each step we add 13000 (+6000) and offset it with adding 5000 three times (-2000,-2000,-2000) to keep the median. So each step adds minimum 4 members.
Therefore, we would have 3, 7, 11, 15... members after each addition, and 11 is lowest number greater than 10 that satisfies initial conditions.

Is my thinking right here?
Expert Post
1 KUDOS received
Veritas Prep GMAT Instructor
User avatar
G
Joined: 16 Oct 2010
Posts: 7960
Location: Pune, India
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 11 May 2017, 07:52
1
This post received
KUDOS
Expert's post
kivalo wrote:
Hi VeritasPrepKarishma .
Could you check would my reasoning be correct, If the questiion was the original one. I want to check this concept on a similar problem. So here is the old version: An automated manufacturing unit employs N experts. Their average monthly salary is $7000 while the median monthly salary is only $5000. If the range of their monthly salaries is $10,000, what is the minimum value of N? (so there is no condition saying that mean is 7000 above lowest salary)

Here is how I would do it: Start with 3000, 5000, 13000, try to get N>10 and keep mean at 7000 and mode at 5000(If I am right starting with mean 7000 minimizes number of additions needed to be done - I want to contrast this with starting with 0, 5000, 10000).
We want to add the least number of elements possible, so in each step we add 13000 (+6000) and offset it with adding 5000 three times (-2000,-2000,-2000) to keep the median. So each step adds minimum 4 members.
Therefore, we would have 3, 7, 11, 15... members after each addition, and 11 is lowest number greater than 10 that satisfies initial conditions.

Is my thinking right here?



In case your mean and median are not with reference to the lowest value, then 3000, 5000, 13000 is a case that satisfies all conditions. Why would you want N to be greater than 10?
N certainly cannot be 1 and 2 (with 2 elements, mean = median)
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Manager
Manager
User avatar
S
Joined: 20 Sep 2016
Posts: 122
GMAT 1: 680 Q49 V35
GPA: 3.99
Re: An automated manufacturing unit employs N experts such that the range [#permalink]

Show Tags

New post 11 May 2017, 08:27
VeritasPrepKarishma wrote:
kivalo wrote:
Hi VeritasPrepKarishma .
Could you check would my reasoning be correct, If the questiion was the original one. I want to check this concept on a similar problem. So here is the old version: An automated manufacturing unit employs N experts. Their average monthly salary is $7000 while the median monthly salary is only $5000. If the range of their monthly salaries is $10,000, what is the minimum value of N? (so there is no condition saying that mean is 7000 above lowest salary)

Here is how I would do it: Start with 3000, 5000, 13000, try to get N>10 and keep mean at 7000 and mode at 5000(If I am right starting with mean 7000 minimizes number of additions needed to be done - I want to contrast this with starting with 0, 5000, 10000).
We want to add the least number of elements possible, so in each step we add 13000 (+6000) and offset it with adding 5000 three times (-2000,-2000,-2000) to keep the median. So each step adds minimum 4 members.
Therefore, we would have 3, 7, 11, 15... members after each addition, and 11 is lowest number greater than 10 that satisfies initial conditions.

Is my thinking right here?



In case your mean and median are not with reference to the lowest value, then 3000, 5000, 13000 is a case that satisfies all conditions. Why would you want N to be greater than 10?
N certainly cannot be 1 and 2 (with 2 elements, mean = median)


No particular reasons, the older version of the question from this topic that I found had all the answer choices greater than 10, even though N is minimized when n = 3 (probably that's why wording is now changed). I just wanted to check whether I would be able to make n>10 anyway, to practice this concept (I wasn't able to ind similar questions).
Thank you for replying!
Re: An automated manufacturing unit employs N experts such that the range   [#permalink] 11 May 2017, 08:27
Display posts from previous: Sort by

An automated manufacturing unit employs N experts such that the range

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.