Find all School-related info fast with the new School-Specific MBA Forum

It is currently 19 Sep 2014, 04:04

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Set V consists of 2 distinct positive values. What is the

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
User avatar
Status: Patience + Belief + Hard Work = Victory
Joined: 30 Apr 2012
Posts: 1
Location: India
GPA: 3.52
WE: Engineering (Computer Software)
Followers: 0

Kudos [?]: 6 [0], given: 0

Set V consists of 2 distinct positive values. What is the [#permalink] New post 05 May 2012, 07:47
5
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

37% (02:04) correct 63% (00:54) wrong based on 105 sessions
Set V consists of 2 distinct positive values. What is the standard deviation of set V?

(1) The mean of the set is 10.
(2) The range of the set is 10.
[Reveal] Spoiler: OA

_________________

Arise, Awake and Stop not till the goal is reached


Last edited by Bunuel on 31 May 2014, 15:05, edited 1 time in total.
Edited the OA.
Director
Director
User avatar
Status:
Joined: 24 Jul 2011
Posts: 557
GMAT 1: 780 Q51 V48
GRE 1: 1540 Q800 V740
Followers: 62

Kudos [?]: 281 [0], given: 11

Re: Set V consists of 2 distinct positive values. What is the [#permalink] New post 06 May 2012, 01:30
The answer seems to be (B) here.

Statement (1) is insufficient: Just knowing the mean is not enough.
Statement (2):
Let the numbers be x and x+10
Then their mean = x+5
S.D. = sqrt (50/2) = 5
Sufficient.

(B) it is.
_________________

GyanOne | http://www.GyanOne.com | +91 9899831738

Get a free detailed MBA profile evaluation

Top MBA Rankings and MBA Admissions blog


Image

Intern
Intern
User avatar
Joined: 04 Apr 2012
Posts: 3
Followers: 0

Kudos [?]: 2 [0], given: 0

Re: Set V consists of 2 distinct positive values. What is the [#permalink] New post 06 May 2012, 08:23
The answer has to be B.
After simplifying the question, we can arrive to below:
Let's assume the 2 distinct +ve numbers as x and y. Assuming y>x.
Mean= x+y/2
S.D = SQRT(((x+y/2) -x)^2 + (y-(x+y/2))^2)/2)
=SQRT(((x+y-2x)/2)^2 + ((2y-y-x)/2)^2/2)
=SQRT((y-x)^2/2)
=y-x/sqrt(2)...so we just need to know the diff between y and x and we get it from the 2nd statement which gives us the range.

Cheers!
1 KUDOS received
SVP
SVP
User avatar
Joined: 06 Sep 2013
Posts: 1666
Location: United States
Concentration: Finance
GMAT 1: 710 Q48 V39
WE: Corporate Finance (Investment Banking)
Followers: 12

Kudos [?]: 164 [1] , given: 274

GMAT ToolKit User
Re: Set V consists of 2 distinct positive values. What is the [#permalink] New post 31 May 2014, 10:53
1
This post received
KUDOS
I also got B

Since the range is 10, in SD only the spread matters, hence 1 and 11 will have the same SD as 2 and 12, and as 3 and 13 etc...

Therefore B

Please clarify cause answer is given as E

Thanks!
Cheers
J
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23480
Followers: 3500

Kudos [?]: 26414 [0], given: 2710

Re: Set V consists of 2 distinct positive values. What is the [#permalink] New post 31 May 2014, 15:06
Expert's post
jlgdr wrote:
I also got B

Since the range is 10, in SD only the spread matters, hence 1 and 11 will have the same SD as 2 and 12, and as 3 and 13 etc...

Therefore B

Please clarify cause answer is given as E

Thanks!
Cheers
J


The correct answer is B. Edited. Thank you.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Joined: 28 May 2014
Posts: 16
Followers: 0

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

Re: Set V consists of 2 distinct positive values. What is the [#permalink] New post 02 Jun 2014, 00:43
We have two numbers. The question is about their standard deviation.

As the mean is ten, we have the following relationship for the two numbers(x1, x2): x1= 10-x, x2= 10+x. This does not help us to calculate the standard deviation. x could be 0, or extremely large.

Statement one is hence insufficient.

We're given the range, meaning that we now have the following relationship for x1 and x2: x1=x, x2=x(+ or -)10.

This helps us. We now know that one of the numbers is 5 above the mean and the other is 5 below the mean. We do not need the actual mean to calculate the deviation.

We get 5^2 and (-5)^2. Finding the variance = (25+25)/2 = 25 And the square root of 25=5 which is our standard deviation. However this was not asked of us.
Re: Set V consists of 2 distinct positive values. What is the   [#permalink] 02 Jun 2014, 00:43
    Similar topics Author Replies Last post
Similar
Topics:
2 Experts publish their posts in the topic Set A consists of all distinct prime numbers which are 2 mor Bunuel 6 17 Feb 2014, 02:54
3 Experts publish their posts in the topic If x and y are distinct positive integers, what is the value ankitmania 4 18 Jul 2010, 07:11
If set consists of distinct numbers such that the difference tania 1 31 Dec 2009, 18:51
Set S consists of distinct numbers such that the difference empty_spaces 4 14 Aug 2007, 21:55
If v1 and v2 are distinct values of v such that kevincan 1 09 Jul 2006, 01:38
Display posts from previous: Sort by

Set V consists of 2 distinct positive values. What is the

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| 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®.