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

It is currently 12 Dec 2018, 00:46

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 in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • The winning strategy for 700+ on the GMAT

     December 13, 2018

     December 13, 2018

     08:00 AM PST

     09:00 AM PST

    What people who reach the high 700's do differently? We're going to share insights, tips and strategies from data we collected on over 50,000 students who used examPAL.
  • GMATbuster's Weekly GMAT Quant Quiz, Tomorrow, Saturday at 9 AM PST

     December 14, 2018

     December 14, 2018

     09:00 AM PST

     10:00 AM PST

    10 Questions will be posted on the forum and we will post a reply in this Topic with a link to each question. There are prizes for the winners.

Is the average (arithmetic mean) of x and y greater than 20?

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51107
Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 15 Dec 2014, 08:19
1
2
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

85% (00:37) correct 15% (01:00) wrong based on 170 sessions

HideShow timer Statistics

Tough and Tricky questions: Number Properties.




Is the average (arithmetic mean) of x and y greater than 20?

(1) The average (arithmetic mean) of 2x and 2y is 48.
(2) x = 3y


Kudos for a correct solution.

_________________

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

Manager
Manager
avatar
Joined: 10 Sep 2014
Posts: 97
Re: Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 15 Dec 2014, 09:24
2
x+y > 20?

statement 1: sufficient
(2x+2y) / 2 = 48. multiply both sides by 2 to remove the fraction, then divide both sides by 2 to remove coefficients of x and y to leave us with x+y=48. The average of x and y will always be 24 for any 2 values according to this statement.

statement 2: insufficient
x=1, y=3, average is 2, less than 20
x=100, y=300, average is 200, greater than 20

Answer A!
Manager
Manager
avatar
Joined: 21 Aug 2010
Posts: 175
Location: United States
GMAT 1: 700 Q49 V35
GMAT ToolKit User
Re: Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 16 Dec 2014, 22:50
1
Bunuel wrote:

Tough and Tricky questions: Number Properties.




Is the average (arithmetic mean) of x and y greater than 20?

(1) The average (arithmetic mean) of 2x and 2y is 48.
(2) x = 3y


Kudos for a correct solution.


1) (2X+2Y)/2 = 48=> (x+y)/2 = 24 sufficient
2) Insufficient as the value cannot be calculated using the onformation given

Ans A
_________________

-------------------------------------

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51107
Re: Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 23 Dec 2014, 05:49
Senior Manager
Senior Manager
User avatar
Status: Math is psycho-logical
Joined: 07 Apr 2014
Posts: 418
Location: Netherlands
GMAT Date: 02-11-2015
WE: Psychology and Counseling (Other)
Re: Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 08 Feb 2015, 02:29
Hello,

[1] is pretty much straight forward.
[2] i guess also is not too complicated, but as I didn't see what I did I am posting it, just in case it was wrong..

So, we are looking for (x+y)/2 and whether it is more than 20.
Substituting x for 3y in the equation above we get:

(3y+y)/2 = 4y/2 = 2y. We don't know what y is, so insufficient. Leading to ANS A.
Intern
Intern
avatar
B
Joined: 19 May 2016
Posts: 29
Location: United States
Concentration: Strategy, Human Resources
GMAT 1: 710 Q46 V41
GMAT 2: 730 Q49 V41
GMAT 3: 680 Q46 V37
WE: Operations (Manufacturing)
Reviews Badge
Re: Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 21 Jul 2016, 11:22
Bunuel wrote:

Tough and Tricky questions: Number Properties.




Is the average (arithmetic mean) of x and y greater than 20?

(1) The average (arithmetic mean) of 2x and 2y is 48.
(2) x = 3y


Kudos for a correct solution.



When I was solving this problem, I got statement one right, but when I got to statement 2, I got Y>10, and X>30, and assumed that X+Y must then be greater than 40. Am I missing something? Please help me clarify.

Thank you!
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51107
Re: Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 21 Jul 2016, 12:55
toby001 wrote:
Bunuel wrote:

Tough and Tricky questions: Number Properties.




Is the average (arithmetic mean) of x and y greater than 20?

(1) The average (arithmetic mean) of 2x and 2y is 48.
(2) x = 3y


Kudos for a correct solution.



When I was solving this problem, I got statement one right, but when I got to statement 2, I got Y>10, and X>30, and assumed that X+Y must then be greater than 40. Am I missing something? Please help me clarify.

Thank you!


For (2) we only know that x = 3y. How did you get that y > 10 and x > 30 from that?
_________________

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

Intern
Intern
avatar
B
Joined: 19 May 2016
Posts: 29
Location: United States
Concentration: Strategy, Human Resources
GMAT 1: 710 Q46 V41
GMAT 2: 730 Q49 V41
GMAT 3: 680 Q46 V37
WE: Operations (Manufacturing)
Reviews Badge
Re: Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 21 Jul 2016, 13:24
Bunuel wrote:
toby001 wrote:
Bunuel wrote:

Tough and Tricky questions: Number Properties.




Is the average (arithmetic mean) of x and y greater than 20?

(1) The average (arithmetic mean) of 2x and 2y is 48.
(2) x = 3y


Kudos for a correct solution.



When I was solving this problem, I got statement one right, but when I got to statement 2, I got Y>10, and X>30, and assumed that X+Y must then be greater than 40. Am I missing something? Please help me clarify.

Thank you!


For (2) we only know that x = 3y. How did you get that y > 10 and x > 30 from that?


I'm starting to feel like I did something stupid here, or I'm reading somewthing wrong. Anyway, Using the inequality and the eauation given in (2), I solved for X and Y.
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51107
Re: Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 21 Jul 2016, 20:50
toby001 wrote:
Bunuel wrote:
toby001 wrote:

Tough and Tricky questions: Number Properties.




Is the average (arithmetic mean) of x and y greater than 20?

(1) The average (arithmetic mean) of 2x and 2y is 48.
(2) x = 3y



When I was solving this problem, I got statement one right, but when I got to statement 2, I got Y>10, and X>30, and assumed that X+Y must then be greater than 40. Am I missing something? Please help me clarify.

Thank you!


For (2) we only know that x = 3y. How did you get that y > 10 and x > 30 from that?


I'm starting to feel like I did something stupid here, or I'm reading somewthing wrong. Anyway, Using the inequality and the eauation given in (2), I solved for X and Y.


From the stem we have a question: Is the average (arithmetic mean) of x and y greater than 20? Is (x + y)/2 > 20? This is not given to be true, this is the question we need to answer.
_________________

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

Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2629
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 21 Dec 2016, 16:00
Nice one.
Here is my solution to this one =>

For mean to be less than 20 => a+b<40

Statement 1-->
2a+2b=2*48
Hence a+b=48
Sufficient => NO,a+b is not less than 40
Hence sufficient
Statement 2-->

Using test cases =>
3,1 => YES
1000,2000=> NO

Hence not sufficient

Hence A

_________________


MBA Financing:- INDIAN PUBLIC BANKS vs PRODIGY FINANCE!

Getting into HOLLYWOOD with an MBA!

The MOST AFFORDABLE MBA programs!

STONECOLD's BRUTAL Mock Tests for GMAT-Quant(700+)

AVERAGE GRE Scores At The Top Business Schools!

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 9124
Premium Member
Re: Is the average (arithmetic mean) of x and y greater than 20?  [#permalink]

Show Tags

New post 27 Sep 2018, 07:33
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

GMAT Club Bot
Re: Is the average (arithmetic mean) of x and y greater than 20? &nbs [#permalink] 27 Sep 2018, 07:33
Display posts from previous: Sort by

Is the average (arithmetic mean) of x and y greater than 20?

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


Copyright

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®.