GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 22 Jun 2018, 19:04

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

Both a set S and a set P have the same number of elements. Is a standa

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

Hide Tags

Expert Post
Math Revolution GMAT Instructor
User avatar
D
Joined: 16 Aug 2015
Posts: 5600
GMAT 1: 800 Q59 V59
GPA: 3.82
Both a set S and a set P have the same number of elements. Is a standa [#permalink]

Show Tags

New post 10 Sep 2016, 21:42
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

61% (00:38) correct 39% (00:31) wrong based on 71 sessions

HideShow timer Statistics

Both a set S and a set P have the same number of elements. Is a standard deviation of the set P smaller than the standard deviation of the set S?
1) All elements of the set P is multiples of 3.
2) All elements of the set S is multiples of 9.

*An answer will be posted in 2 days.

_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $99 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Board of Directors
User avatar
V
Status: Stepping into my 10 years long dream
Joined: 18 Jul 2015
Posts: 3651
Premium Member Reviews Badge CAT Tests
Re: Both a set S and a set P have the same number of elements. Is a standa [#permalink]

Show Tags

New post 10 Sep 2016, 22:52
MathRevolution wrote:
Both a set S and a set P have the same number of elements. Is a standard deviation of the set P smaller than the standard deviation of the set S?
1) All elements of the set P is multiples of 3.
2) All elements of the set S is multiples of 9.

*An answer will be posted in 2 days.


Answer E.

Statement 1 : No information about Set S. - Insufficient

Statement 2 : No information about Set P. - Insufficient

Combining, It could happen that all the elements of Set P are also multiple of 9. Hence, in that case there would be Zero SD and if not, then there would be some SD. Hence, insufficient.
_________________

My GMAT Story: From V21 to V40
My MBA Journey: My 10 years long MBA Dream
My Secret Hacks: Best way to use GMATClub
Verbal Resources: All SC Resources at one place | All CR Resources at one place
Blog: Subscribe to Question of the Day Blog

GMAT Club Inbuilt Error Log Functionality - View More.
NEW VISA FORUM - Ask all your Visa Related Questions - here.

How to use an Error Log? Check out my tips!



Find a bug in the new email templates and get rewarded with 2 weeks of GMATClub Tests for free

Senior Manager
Senior Manager
avatar
Joined: 23 Apr 2015
Posts: 322
Location: United States
Concentration: General Management, International Business
WE: Engineering (Consulting)
Re: Both a set S and a set P have the same number of elements. Is a standa [#permalink]

Show Tags

New post 10 Sep 2016, 22:55
MathRevolution wrote:
Both a set S and a set P have the same number of elements. Is a standard deviation of the set P smaller than the standard deviation of the set S?
1) All elements of the set P is multiples of 3.
2) All elements of the set S is multiples of 9.

*An answer will be posted in 2 days.


There is no mention about the elements in the set P and S except they are multiples of 3 and 9 respectively. It's possible that both the set has only 0's as their elements.
And since 0 is a multiple of every number, SD is zero. But if we assume any other elements other than zero, the SD is different.

Answer is E.
Manager
Manager
avatar
Joined: 28 Jun 2016
Posts: 207
Location: Canada
Concentration: Operations, Entrepreneurship
Re: Both a set S and a set P have the same number of elements. Is a standa [#permalink]

Show Tags

New post 10 Sep 2016, 23:04
To find standard deviation, we need arithmetic mean, individual elements and number of elements.

Statement 1:

Doesn't have information about set S.

Insufficient

Statement 2:

Doesn't have information about set P.

Insufficient

St 1 & 2:

No information about nature of elements.

For example:
If,
P= {3, 3, 3}
S={9,9,9}

Then standard deviation of both sets= 0.
It gives a clear NO.

On the other hand,

P={3,3,3}
S={9,45,99}

Std dev of P= 0
Std dev of S>0

YES

Insufficient


IMO E


Sent from my iPhone using GMAT Club Forum mobile app
Expert Post
Math Revolution GMAT Instructor
User avatar
D
Joined: 16 Aug 2015
Posts: 5600
GMAT 1: 800 Q59 V59
GPA: 3.82
Re: Both a set S and a set P have the same number of elements. Is a standa [#permalink]

Show Tags

New post 12 Sep 2016, 08:59
From the original condition, we have to know all elements of the set S. Hence, there is a high chance that E is the correct answer. Using 1) & 2), P={3,6,9}, S={9,18,27} yes, P={3, 30,300}, S={9,18,27} no. Hence, the conditions are not sufficient, and the correct answer is E.
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $99 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Intern
Intern
avatar
B
Joined: 14 Aug 2015
Posts: 4
Re: Both a set S and a set P have the same number of elements. Is a standa [#permalink]

Show Tags

New post 02 Apr 2017, 05:09
Trap : One might end up assuming that the set contains consecutive multiple of 3s and 9s. Then one might end up with 'C' as answer.

Avoid this trap and 'E' could be the only answer.
Re: Both a set S and a set P have the same number of elements. Is a standa   [#permalink] 02 Apr 2017, 05:09
Display posts from previous: Sort by

Both a set S and a set P have the same number of elements. Is a standa

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


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.