It is currently Fri Feb 03, 2012 6:58 pm




   Post new topic Reply to topic      [ 21 posts ]  Bookmark and Share Oldest Best Reply Go to page 1, 2  Next
Author Message
  M24 Q 33 [#permalink]
New postPosted: Thu Mar 12, 2009 1:59 pm 
Offline
SVP
SVP
User avatar

Joined: Sat Jul 05, 2008
Posts: 1583
Followers: 25

Kudos (?): 128 (0), given: 1

GMAT Tests User
If sets S and T are united into a single set, will the mean of this set be smaller than the sum of means of sets S and T ?

1. S and T are one-element sets
2. Neither set S nor set T contains negative numbers

[Reveal] Spoiler: OA
E

Source: GMAT Club Tests - hardest GMAT questions

I will let you guys discuss this. How ever, The two Set opeartions I remember are union and intersection. How are we supposed to interpret merge.


  Profile  
 
Kaplan GMAT Prep Discount CodesKnewton GMAT Discount CodesGMAT Pill GMAT Discount Codes
  Re: M24 Q 33 [#permalink]
New postPosted: Thu Mar 12, 2009 6:06 pm 
Offline
SVP
SVP
User avatar

Joined: Wed Nov 07, 2007
Posts: 2201
Location: New York
Followers: 13

Kudos (?): 230 (0), given: 5

GMAT Tests User
icandy wrote:
If sets S and T are merged into a single set, will the mean of this set be smaller than the sum of means of sets S and T ?

1. S and T are one-element sets
2. Neither set S nor set T contains negative numbers

(C) 2008 GMAT Club - m24#33

* Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient
* Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient
* BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient
* EACH statement ALONE is sufficient
* Statements (1) and (2) TOGETHER are NOT sufficient

I will let you guys discuss this. How ever, The two Set opeartions I remember are union and intersection. How are we supposed to interpret merge.



I believe two operations and "union" and "union all" --> if you know ORACLE sql LANGUAGE. :lol: :lol: :lol:
( I may be wrong.. but thats what I interpret.. as IT .. nerd)

e.g
A ={1,3} B={1,5}

Merge = {1,3,5} ( all distinct elements) avg = 3
Sum = {1,1,3,5} avg= 10/4 = 2.5


another e.g.
A ={1,5} B={3,5}
Merge = {1,3,5} ( all distinct elements) avg = 3
Sum = {1,3,5,5} avg= 14/4 = 3.66



I will go with E.

_________________
Your attitude determines your altitude
Smiling wins more friends than frowning


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Fri Mar 27, 2009 9:47 am 
Offline
VP
VP
User avatar

Joined: Tue Apr 01, 2008
Posts: 1011
Location: Bangalore, Baroda
Followers: 7

Kudos (?): 101 (0), given: 18

GMAT Tests User
Couldnt get this!!
It is sum of the means of A and B.
e.g
A ={1,3} B={1,5}

Merge = {1,3,5} ( all distinct elements) avg = 3
Sum = {1,1,3,5} avg= 10/4 = 2.5 >> cant understand this.

Sum of means should be 2 + 3 = 6.May be my understanding is wrong. Please explain.

x2suresh wrote:
icandy wrote:
If sets S and T are merged into a single set, will the mean of this set be smaller than the sum of means of sets S and T ?

1. S and T are one-element sets
2. Neither set S nor set T contains negative numbers

(C) 2008 GMAT Club - m24#33

* Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient
* Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient
* BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient
* EACH statement ALONE is sufficient
* Statements (1) and (2) TOGETHER are NOT sufficient

I will let you guys discuss this. How ever, The two Set opeartions I remember are union and intersection. How are we supposed to interpret merge.



I believe two operations and "union" and "union all" --> if you know ORACLE sql LANGUAGE. :lol: :lol: :lol:
( I may be wrong.. but thats what I interpret.. as IT .. nerd)

e.g
A ={1,3} B={1,5}

Merge = {1,3,5} ( all distinct elements) avg = 3
Sum = {1,1,3,5} avg= 10/4 = 2.5


another e.g.
A ={1,5} B={3,5}
Merge = {1,3,5} ( all distinct elements) avg = 3
Sum = {1,3,5,5} avg= 14/4 = 3.66



I will go with E.


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Sun Mar 29, 2009 7:37 pm 
Offline
CEO
CEO
User avatar

Joined: Wed Aug 29, 2007
Posts: 2945
Followers: 27

Kudos (?): 285 (0), given: 19

GMAT Tests User
icandy wrote:
If sets S and T are merged into a single set, will the mean of this set be smaller than the sum of means of sets S and T ?

1. S and T are one-element sets
2. Neither set S nor set T contains negative numbers

I will let you guys discuss this. How ever, The two Set opeartions I remember are union and intersection. How are we supposed to interpret merge.


For me merged = combined.

1: S and T are one-element sets
If S = T = 2, mean of the merged set (2, 2) = 2 and sum of the means of sets S and T is 4.
If S = 2, and T = -2, mean of the merged set (2, -2) = 0 and sum of the means of sets S and T is 0.
If S = 0, and T = 0, mean of the merged set (2, 2) = 0 and sum of the means of sets S and T is 0. NSF..

2: Neither set S nor set T contains negative numbers
If S = T = 2, mean of the merged set (2, 2) = 2 and sum of the means of sets S and T is 4.
If S = 0, and T = 0, mean of the merged set (2, 2) = 0 and sum of the means of sets S and T is 0. NSF.

Togather alos nsf.
E.

_________________
Verbal: new-to-the-verbal-forum-please-read-this-first-77546.html
Math: new-to-the-math-forum-please-read-this-first-77764.html
Gmat: everything-you-need-to-prepare-for-the-gmat-revised-77983.html


GT


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Sun Mar 29, 2009 8:39 pm 
Offline
Manager
Manager

Joined: Mon May 19, 2008
Posts: 205
Location: Mumbai
Followers: 1

Kudos (?): 2 (0), given: 0

GMAT Tests User
Answer should be E - not sufficient in any of the cases.
What's the OA?


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Mon Mar 30, 2009 3:32 am 
Offline
CIO
CIO

Joined: Tue Oct 02, 2007
Posts: 1528
Followers: 48

Kudos (?): 392 (0), given: 330

GMAT ToolKit User GMAT Tests User
The OA is E.

Do you guys think we should replace "merged" with "united" in the question stem?

_________________
Welcome to GMAT Club! :)
Want to solve GMAT questions on the go? GMAT Club iPhone app will help.
Please read this before posting in GMAT Club Tests forum
Result correlation between real GMAT and GMAT Club Tests
GMAT Club Tests Feedback and Reviews
Are GMAT Club Test sets ordered in any way?


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Sun Apr 05, 2009 1:59 am 
Offline
VP
VP
User avatar

Joined: Tue Apr 01, 2008
Posts: 1011
Location: Bangalore, Baroda
Followers: 7

Kudos (?): 101 (0), given: 18

GMAT Tests User
Yes that should be better...United or union of two sets....merged is confusing :(
dzyubam wrote:
The OA is E.

Do you guys think we should replace "merged" with "united" in the question stem?


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Thu Mar 11, 2010 6:22 am 
Offline
Manager
Manager

Joined: Mon Jan 07, 2008
Posts: 96
Followers: 2

Kudos (?): 9 (0), given: 1

GMAT Tests User
Merge of sets means you need to combine.

S= {1}
T= {1,2}

Merge = {1,1,2}


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Thu Mar 11, 2010 7:07 am 
Offline
Intern
Intern

Joined: Mon Jan 11, 2010
Posts: 11
Followers: 0

Kudos (?): 5 (0), given: 2

Both solution 1 and 2 fail the zero test.

S1: S = {0} and T = {0} => Mean of S = 0 and Mean of T = 0
Set ST = {0, 0} => Mean of ST = 0
Thus, S1 is not sufficient.

S2. Neither S nor T contain negative number.
Take the same sets: S = {0} and T = {0}
S2 is not sufficient.

Answer is E.


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Thu Mar 11, 2010 7:35 am 
Offline
Senior Manager
Senior Manager

Joined: Mon Feb 01, 2010
Posts: 300
Followers: 1

Kudos (?): 25 (0), given: 2

GMAT Tests User
icandy wrote:
If sets S and T are united into a single set, will the mean of this set be smaller than the sum of means of sets S and T ?

1. S and T are one-element sets
2. Neither set S nor set T contains negative numbers

[Reveal] Spoiler: OA
E

Source: GMAT Club Tests - hardest GMAT questions


s= {1,2,3}
mean1 = 2
t= {2,3,4}
mean2 = 3
sUt= {1,2,3,4}
mean3= 2.5 < mean1 + mean2

s={-1,-2,-3}
mean1 = -2
t={-2,-3,-4}
mean2 = -3
sUt= {-1,-2,-3,-4}
mean3 = -2.5 > mean1 + mean2

s={0}
mean1 = 0
t = {0}
mean2 = 0
sUt = {0}
mean3 = 0 = mean1+mean2

hence none of the two stmts solve this questions. Hence E.


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Thu Mar 11, 2010 3:26 pm 
Offline
Manager
Manager

Joined: Sun Feb 04, 2007
Posts: 89
Followers: 1

Kudos (?): 24 (0), given: 16

GMAT Tests User
vshrivastava wrote:
Both solution 1 and 2 fail the zero test.

S1: S = {0} and T = {0} => Mean of S = 0 and Mean of T = 0
Set ST = {0, 0} => Mean of ST = 0
Thus, S1 is not sufficient.

S2. Neither S nor T contain negative number.
Take the same sets: S = {0} and T = {0}
S2 is not sufficient.

Answer is E.



You only showed that you can answer the question with a definite NO.
The question being "will the mean of this set be smaller than the sum of means of sets S and T ?"

This sufficiently answers the question as a NO for both cases.

In order for the cases to be insufficient, you need to be able answer the question with both a yes and a no.

_________________
If you like my post, a kudos is always appreciated ;)


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Sun Mar 14, 2010 1:53 am 
Offline
Senior Manager
Senior Manager

Joined: Fri Mar 05, 2010
Posts: 260
Followers: 1

Kudos (?): 13 (0), given: 8

friends
i understand that both options failed the zero test but why do we need a zero in set

ex- a set of 3 pen, 2 pencil and 0 flower
we can simply say it a set of 3 pen and 2 pencils, why do we consider something like zero in a set

Please explain


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Fri Mar 19, 2010 7:18 am 
Offline
Senior Manager
Senior Manager
User avatar

Joined: Sun Dec 13, 2009
Posts: 283
Followers: 2

Kudos (?): 51 (0), given: 13

GMAT Tests User
hardnstrong wrote:
friends
i understand that both options failed the zero test but why do we need a zero in set

ex- a set of 3 pen, 2 pencil and 0 flower
we can simply say it a set of 3 pen and 2 pencils, why do we consider something like zero in a set

Please explain


Zero is considered as an entity here.
like A has 0 sets of readings 2m , 0m, 1m
so zero is the value.

_________________
My debrief: done-and-dusted-730-q49-v40


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Sat Mar 20, 2010 5:23 am 
Offline
Senior Manager
Senior Manager

Joined: Mon Dec 21, 2009
Posts: 364
Concentration: Entrepreneurship, Finance
Followers: 3

Kudos (?): 61 (0), given: 10

GMAT Tests User
hardnstrong wrote:
friends
i understand that both options failed the zero test but why do we need a zero in set

ex- a set of 3 pen, 2 pencil and 0 flower
we can simply say it a set of 3 pen and 2 pencils, why do we consider something like zero in a set

Please explain

"zero" in this case does not imply an empty set; rather, it it a set consisting of an element-digit 0.

_________________
KUDOS me if you feel my contribution has helped you.


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Sat Mar 20, 2010 7:48 am 
Offline
Senior Manager
Senior Manager

Joined: Fri Mar 05, 2010
Posts: 260
Followers: 1

Kudos (?): 13 (0), given: 8

thanks ...........sidhu n gmatbull

_________________
Success is my Destiny


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Mon Sep 06, 2010 11:36 pm 
Offline
Manager
Manager

Joined: Mon Jul 12, 2010
Posts: 151
Followers: 1

Kudos (?): 1 (0), given: 3

E.


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Wed Dec 08, 2010 2:45 am 
Offline
Intern
Intern

Joined: Tue Nov 23, 2010
Posts: 9
Followers: 1

Kudos (?): 0 (0), given: 20

I think the answer should be C.
(1) and (2) says S = {s} (mean = s) and T = {t} (mean = t), united = {s, t} (mean = (s+t)/2)
s, t = non negative.
Question: s+t < (s+t)/2 ????
If s = t = 0, the answer to the question "will the mean of this set be smaller than the sum of means of sets S and T?" is NO.
If s = 0, t > 0 (and vice versa), the answer to question "will the mean of this set be smaller than the sum of means of sets S and T?" is NO.
If s, t > 0, the answer to the question "will the mean of the set be smaller than the sum of means of sets S and T?" is still NO.
In any case, the answer is still NO. Then (1) and (2) together are sufficient enough.
Why is E the correct answer????


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Tue Mar 15, 2011 5:19 am 
Offline
SVP
SVP
User avatar

Joined: Tue Nov 16, 2010
Posts: 1662
Location: Singapore
Concentration: Strategy, Technology
Followers: 12

Kudos (?): 137 (0), given: 27

GMAT Tests User
The answer is E.

Let A = {2}, B = {3},

So the mean of merge is 2.5, which is < 5

Let A = {1}, B = {1}

So the mean of merge is 1, which is equal to mean of either set.

_________________
Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Tue Mar 15, 2011 6:38 am 
Offline
Manager
Manager

Joined: Fri Feb 11, 2011
Posts: 203
Followers: 1

Kudos (?): 0 (0), given: 0

GMAT Tests User
yes it is E...failure case is when they have 0 as an element


  Profile  
 
  Re: M24 Q 33 [#permalink]
New postPosted: Tue Mar 15, 2011 9:48 pm 
Offline
Manager
Manager

Status: A continuous journey of self-improvement is essential for every person -Socrates
Joined: Sun Jan 02, 2011
Posts: 87
Followers: 1

Kudos (?): 0 (0), given: 14

firasath wrote:
vshrivastava wrote:
Both solution 1 and 2 fail the zero test.

S1: S = {0} and T = {0} => Mean of S = 0 and Mean of T = 0
Set ST = {0, 0} => Mean of ST = 0
Thus, S1 is not sufficient.

S2. Neither S nor T contain negative number.
Take the same sets: S = {0} and T = {0}
S2 is not sufficient.

Answer is E.



You only showed that you can answer the question with a definite NO.
The question being "will the mean of this set be smaller than the sum of means of sets S and T ?"

This sufficiently answers the question as a NO for both cases.

In order for the cases to be insufficient, you need to be able answer the question with both a yes and a no.


I think, vshrivastava has shown that both statement put together also we are getting two answer: one time > and other time =. This much is enough to tell that answer is E.


  Profile  
 
Online
gmatclubot
Display posts from previous:  Sort by  

Post new topic Reply to topic  [ 21 posts ]  Go to page 1, 2  Next

 Similar topics   Author   Replies   Views   Last post 
M24 Q 24

in GMAT Club Tests

icandy

10

1758

Thu Mar 12, 2009 1:54 pm

M24 Q 30

in GMAT Club Tests

mirzohidjon

3

381

Mon Jan 18, 2010 6:54 pm

m24 q16

in GMAT Club Tests

pc80

3

392

Fri Apr 16, 2010 6:26 pm

M24 Q22

in GMAT Club Tests

gmat00

3

170

Tue May 04, 2010 7:38 am

m24Q30

in GMAT Club Tests

martie11

2

47

Tue Oct 25, 2011 6:16 pm





Who is online

Users browsing this forum: No registered users and 0 guests


Search for:
Jump to:




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 GMAT (C) is a registered trademark of the Graduate Management Admission Council, and this site has neither been reviewed nor endorsed by GMAC.