It is currently 21 Nov 2017, 05:30

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

For a certain set of n numbers, where n > 2, is the average (arithmet

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42280

Kudos [?]: 132894 [0], given: 12391

For a certain set of n numbers, where n > 2, is the average (arithmet [#permalink]

Show Tags

New post 14 Jan 2015, 02:50
Expert's post
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  85% (hard)

Question Stats:

33% (01:26) correct 67% (01:20) wrong based on 82 sessions

HideShow timer Statistics

For a certain set of n numbers, where n > 2, is the average (arithmetic mean) equal to the median?

(1) The n numbers are positive, consecutive even integers.
(2) The average of the n numbers is equal to the average of the largest and smallest numbers in the set.

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

Kudos [?]: 132894 [0], given: 12391

Manager
Manager
avatar
Joined: 31 Jul 2014
Posts: 147

Kudos [?]: 57 [0], given: 373

GMAT 1: 630 Q48 V29
Re: For a certain set of n numbers, where n > 2, is the average (arithmet [#permalink]

Show Tags

New post 15 Jan 2015, 06:11
Bunuel wrote:
For a certain set of n numbers, where n > 2, is the average (arithmetic mean) equal to the median?

(1) The n numbers are positive, consecutive even integers.
(2) The average of the n numbers is equal to the average of the largest and smallest numbers in the set.

Kudos for a correct solution.


stat1. The n numbers are positive, consecutive even integers.
For consecutive integers, arithmatic mean = Median
e.g. 2 4 6 8 am=5 and median = avg of middle 2 numbers = (4+6)/2 =5 --> am = median
e.g 2 4 6 8 10 am=30/5=6 and median = 6

suff

stat2
The average of the n numbers is equal to the average of the largest and smallest numbers in the set.
avg=(a1+an) / 2 --> This is also property of consecutive integers.
and for all consecutive integers --> am=median

suff

IMO : D

Pls correct me if I am wrong, Many Thanks

Kudos [?]: 57 [0], given: 373

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42280

Kudos [?]: 132894 [0], given: 12391

Re: For a certain set of n numbers, where n > 2, is the average (arithmet [#permalink]

Show Tags

New post 19 Jan 2015, 04:30
Bunuel wrote:
For a certain set of n numbers, where n > 2, is the average (arithmetic mean) equal to the median?

(1) The n numbers are positive, consecutive even integers.
(2) The average of the n numbers is equal to the average of the largest and smallest numbers in the set.

Kudos for a correct solution.


The correct answer is A.
_________________

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

Kudos [?]: 132894 [0], given: 12391

Expert Post
5 KUDOS received
EMPOWERgmat Instructor
User avatar
P
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 10143

Kudos [?]: 3523 [5], given: 173

Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: 340 Q170 V170
Re: For a certain set of n numbers, where n > 2, is the average (arithmet [#permalink]

Show Tags

New post 19 Jan 2015, 19:32
5
This post received
KUDOS
Expert's post
Hi anupamadw,

Many DS questions include some type of "test" of your thoroughness - in other words, "do you 'see' more than just the 'obvious' answer?"

Here, your understanding of the concepts is strong when you're focused on positive integers. But what happens when the integers are NOT positive.....?

You properly assessed Fact 1, so I won't rehash any of that work here. Notice how Fact 1 "restricted" you to POSITIVE, CONSECUTIVE, EVEN integers? NONE of those restrictions exist in Fact 2...

Consider this set of numbers: {-1, 0, 6, 6, 9}

The average of the group = 4
The average of the smallest and biggest = 4
The median of the group = 6
Here, the average is NOT = to the median, so the answer to the question is NO.

You already have some examples that show that the answer could be YES.
Fact 2 is INSUFFICIENT.

To be fair, most DS questions don't require that you do too much to "break" a pattern in the possible answers, but you have to be ready to consider more than just the obvious. Here, the "obvious" was "positive integers and no duplicates."

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!***********************

Kudos [?]: 3523 [5], given: 173

Manager
Manager
avatar
Joined: 31 Jul 2014
Posts: 147

Kudos [?]: 57 [0], given: 373

GMAT 1: 630 Q48 V29
Re: For a certain set of n numbers, where n > 2, is the average (arithmet [#permalink]

Show Tags

New post 20 Jan 2015, 05:15
EMPOWERgmatRichC wrote:
Hi anupamadw,

Many DS questions include some type of "test" of your thoroughness - in other words, "do you 'see' more than just the 'obvious' answer?"

Here, your understanding of the concepts is strong when you're focused on positive integers. But what happens when the integers are NOT positive.....?

You properly assessed Fact 1, so I won't rehash any of that work here. Notice how Fact 1 "restricted" you to POSITIVE, CONSECUTIVE, EVEN integers? NONE of those restrictions exist in Fact 2...

Consider this set of numbers: {-1, 0, 6, 6, 9}

The average of the group = 4
The average of the smallest and biggest = 4
The median of the group = 6
Here, the average is NOT = to the median, so the answer to the question is NO.

You already have some examples that show that the answer could be YES.
Fact 2 is INSUFFICIENT.

To be fair, most DS questions don't require that you do too much to "break" a pattern in the possible answers, but you have to be ready to consider more than just the obvious. Here, the "obvious" was "positive integers and no duplicates."

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


Thanks for explaination, +1 to you

Kudos [?]: 57 [0], given: 373

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 15582

Kudos [?]: 283 [0], given: 0

Premium Member
Re: For a certain set of n numbers, where n > 2, is the average (arithmet [#permalink]

Show Tags

New post 19 Oct 2017, 04:51
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

Kudos [?]: 283 [0], given: 0

Re: For a certain set of n numbers, where n > 2, is the average (arithmet   [#permalink] 19 Oct 2017, 04:51
Display posts from previous: Sort by

For a certain set of n numbers, where n > 2, is the average (arithmet

  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®.