Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

It is currently 28 May 2017, 03:55

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

What is the minimum percentage increase in the mean of set X

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

Hide Tags

1 KUDOS received
Senior Manager
Senior Manager
avatar
Joined: 07 Nov 2009
Posts: 305
Followers: 9

Kudos [?]: 592 [1] , given: 20

What is the minimum percentage increase in the mean of set X [#permalink]

Show Tags

New post 26 Jan 2012, 12:32
1
This post received
KUDOS
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

74% (01:45) correct 26% (01:05) wrong based on 228 sessions

HideShow timer Statistics

What is the minimum percentage increase in the mean of set X {-4, -1, 0, 6, 9} if its two smallest elements are replaced with two different primes?
(A) 25%
(B) 50%
(C) 75%
(D) 100%
(E) 200%
[Reveal] Spoiler: OA
Expert Post
1 KUDOS received
Math Expert
User avatar
P
Joined: 02 Sep 2009
Posts: 38953
Followers: 7747

Kudos [?]: 106402 [1] , given: 11626

Re: minimum percentage increase [#permalink]

Show Tags

New post 26 Jan 2012, 12:39
1
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
rohitgoel15 wrote:
What is the minimum percentage increase in the mean of set X {-4, -1, 0, 6, 9} if its two smallest elements are replaced with two different primes?
(A) 25%
(B) 50%
(C) 75%
(D) 100%
(E) 200%


Mean of X is (-4-1+0+6+9)/5=2;

In order the increase to be minimal we should replace two smallest elements of X, which are -4 and -1, with two smallest primes, which are 2 and 3. Hence our new set will be {2, 3, 0, 6, 9} --> new mean is (2+3+0+6+9)/5=4.

Percent increase=(4-2)/2*100=100%.

Answer: D.
_________________

New to the Math Forum?
Please read this: 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

Expert Post
1 KUDOS received
Math Expert
User avatar
P
Joined: 02 Sep 2009
Posts: 38953
Followers: 7747

Kudos [?]: 106402 [1] , given: 11626

Re: What is the minimum percentage increase in the mean of set X [#permalink]

Show Tags

New post 26 Mar 2012, 09:18
1
This post received
KUDOS
Expert's post
Top Contributor
1 KUDOS received
VP
VP
User avatar
G
Joined: 12 Sep 2015
Posts: 1438
Location: Canada
Followers: 139

Kudos [?]: 1637 [1] , given: 329

Re: What is the minimum percentage increase in the mean of set X [#permalink]

Show Tags

New post 17 Sep 2016, 04:45
1
This post received
KUDOS
Top Contributor
As others have demonstrated, the average of set X increases from 2 to 4
Many students will incorrectly conclude that we have a 200% increase, since 4 is equal to 2 times 2.
This is not the case.
Percent increase = 100(new - old)/old
So, in this case, percent increase = 100(4 - 2)/2
= 200/2
= 100

RELATED VIDEO

_________________

Brent Hanneson – Founder of gmatprepnow.com

Image

1 KUDOS received
Intern
Intern
avatar
Joined: 21 Jul 2016
Posts: 1
Followers: 0

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

Re: What is the minimum percentage increase in the mean of set X {-4, -1, [#permalink]

Show Tags

New post 08 Dec 2016, 20:43
1
This post received
KUDOS
I think D.
Mean in the initial set is 2 (-4-2+0+6+9)/5. We should replace the smallest elements -4 and -1 with prime numbers also the smallest in order to have minimum percentage increase. So we get new set (2,3,0,6,9) with mean 4. So the minimum % increase is 100%

Sent from my SM-A310F using GMAT Club Forum mobile app
Intern
Intern
avatar
Joined: 25 Aug 2010
Posts: 17
Followers: 0

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

Re: What is the minimum percentage increase in the mean of set X [#permalink]

Show Tags

New post 26 Mar 2012, 09:10
hi Bunuel,

request to let me if two smallest primes numbers can be negative?
_________________

regards
eshwar

SVP
SVP
User avatar
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1857
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Followers: 51

Kudos [?]: 2176 [0], given: 193

Re: What is the minimum percentage increase in the mean of set X [#permalink]

Show Tags

New post 01 Mar 2013, 03:09
1 is not a prime number, got to know it now..... was considering it & made the answer wrong :(
_________________

Kindly press "+1 Kudos" to appreciate :)

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 15495
Followers: 651

Kudos [?]: 210 [0], given: 0

Premium Member
Re: What is the minimum percentage increase in the mean of set X [#permalink]

Show Tags

New post 08 Jul 2016, 06:12
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.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Director
Director
User avatar
Joined: 04 Jun 2016
Posts: 654
GMAT 1: 750 Q49 V43
Followers: 63

Kudos [?]: 277 [0], given: 36

Re: What is the minimum percentage increase in the mean of set X [#permalink]

Show Tags

New post 23 Jul 2016, 01:08
rohitgoel15 wrote:
What is the minimum percentage increase in the mean of set X {-4, -1, 0, 6, 9} if its two smallest elements are replaced with two different primes?
(A) 25%
(B) 50%
(C) 75%
(D) 100%
(E) 200%


Current mean is =\(\frac{(-4)+(-1)+(0)+(6)+(9)}{5} = \frac{(-5+15)}{5} = \frac{10}{5} = 2\)

Since we have to find the minimum increase , we should add the smallest distinct prime 2,3
New mean is =\(\frac{(0)+(2)+(3)+(6)+(9)}{5} = \frac{20}{5} = 4\)

Percent change = \(\frac{(New -Old}{Old})* 100 = \frac{4-2}{2}*100\)

Percent change = \(\frac{2}{2}* 100 = 100\) %

Answer is D
_________________

Posting an answer without an explanation is "GOD COMPLEX". The world doesn't need any more gods. Please explain you answers properly.
FINAL GOODBYE :- 17th SEPTEMBER 2016. .. 16 March 2017 - I am back but for all purposes please consider me semi-retired.

Senior Manager
Senior Manager
User avatar
Joined: 11 Nov 2014
Posts: 370
Location: India
Concentration: Finance, International Business
WE: Project Management (Telecommunications)
Followers: 2

Kudos [?]: 30 [0], given: 17

GMAT ToolKit User Premium Member
Re: What is the minimum percentage increase in the mean of set X [#permalink]

Show Tags

New post 17 Sep 2016, 07:48
Bunuel
answer will change if I have 5 & 2 or say 2 & 11, isn't it?
just curious...
BSchool Forum Moderator
avatar
G
Status: Aiming 800 Q51 V51
Joined: 18 Jul 2015
Posts: 1697
Location: India
Concentration: General Management, International Business
GMAT 1: 670 Q50 V32
GMAT 2: 700 Q50 V34
GPA: 3.65
WE: Brand Management (Health Care)
Followers: 39

Kudos [?]: 401 [0], given: 52

Premium Member Reviews Badge
Re: What is the minimum percentage increase in the mean of set X [#permalink]

Show Tags

New post 17 Sep 2016, 07:51
paidlukkha wrote:
Bunuel
answer will change if I have 5 & 2 or say 2 & 11, isn't it?
just curious...


Yes, it will change but notice that we have to determine the minimum change and for that we are taking the lowest possible values as 2 and 3.
_________________

Good Luck

Senior Manager
Senior Manager
User avatar
S
Joined: 26 Oct 2016
Posts: 460
Location: United States
Concentration: Marketing, International Business
Schools: HBS '19
GMAT 1: 770 Q51 V44
GPA: 4
WE: Education (Education)
Followers: 25

Kudos [?]: 64 [0], given: 823

What is the minimum percentage increase in the mean of set X {-4, -1, [#permalink]

Show Tags

New post 08 Dec 2016, 19:58
What is the minimum percentage increase in the mean of set X {-4, -1, 0, 6, 9} if its two smallest elements are replaced with two different primes?
(A) 25% (B) 50% (C) 75% (D) 100% (E) 200%

Stuck with above problem looking for some guidance and assistance.
_________________

Thanks & Regards,
Anaira Mitch

Expert Post
Math Expert
User avatar
P
Joined: 02 Sep 2009
Posts: 38953
Followers: 7747

Kudos [?]: 106402 [0], given: 11626

Re: What is the minimum percentage increase in the mean of set X [#permalink]

Show Tags

New post 09 Dec 2016, 02:09
anairamitch1804 wrote:
What is the minimum percentage increase in the mean of set X {-4, -1, 0, 6, 9} if its two smallest elements are replaced with two different primes?
(A) 25% (B) 50% (C) 75% (D) 100% (E) 200%

Stuck with above problem looking for some guidance and assistance.


Merging topics. Please refer to the discussion above.
_________________

New to the Math Forum?
Please read this: 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

Re: What is the minimum percentage increase in the mean of set X   [#permalink] 09 Dec 2016, 02:09
    Similar topics Author Replies Last post
Similar
Topics:
1 Experts publish their posts in the topic If x and y are positive integers and 4500x = y^3, what is the minimum Bunuel 5 20 Dec 2016, 01:15
16 Experts publish their posts in the topic What is the minimum value of |x-4| + |x+3| + |x-5| ? chetan2u 8 24 May 2017, 14:30
10 Experts publish their posts in the topic Randy is going to flip a coin x times. What is the minimum value of x pacifist85 8 04 Nov 2016, 08:23
6 Experts publish their posts in the topic What will be the percentage increase in the area of the cube JubtaGubar 7 11 Jan 2016, 09:11
2 Experts publish their posts in the topic A set has maximum number 4d above the mean and a minimum gmatbull 3 22 Jan 2011, 11:26
Display posts from previous: Sort by

What is the minimum percentage increase in the mean of set X

  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 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®.