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

It is currently 21 Aug 2018, 01:30

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

During the first 11 months of a recent year, a certain charitable orga

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

Hide Tags

Stern Thread Master
avatar
Joined: 26 Jul 2014
Posts: 65
During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 27 Jul 2014, 11:22
3
4
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

89% (00:53) correct 11% (00:58) wrong based on 314 sessions

HideShow timer Statistics

During the first 11 months of a recent year, a certain charitable organization received an average of $20,600 per month in donations. How much did the organization receive in donations during December of that year if the average amount of donations per month for the entire year was $21,000?

A. $21,400
B. $21,600
C. $24,000
D. $25,400
E. $25,800
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 48074
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 27 Jul 2014, 14:32
9
6
eleuth wrote:
During the first 11 months of a recent year, a certain charitable organization received an average of $20,600 per month in donations. How much did the organization receive in donations during December of that year if the average amount of donations per month for the entire year was $21,000?

A. $21,400
B. $21,600
C. $24,000
D. $25,400
E. $25,800


The average to rise by $400, from $20,600 to $21,000, December donation should compensate those $400 for each of the first 11 months, so should have 11*400 more than $21,000: 11*400 + 21,000 = $25,400.

Answer: D.
_________________

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

General Discussion
Manager
Manager
avatar
Joined: 20 Dec 2013
Posts: 89
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 27 Jul 2014, 12:31
1
1
Say for December month, It is X

then
\(11*(20600) + X = 12 * (21000)\)
=> x = 25400 - Option D
_________________

Best
MKS
Appreciate it with Kudos !! :)

Intern
Intern
User avatar
Joined: 13 Jul 2014
Posts: 10
Location: India
Concentration: Operations, Technology
GMAT Date: 11-06-2014
GRE 1: Q159 V144
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 20 Oct 2014, 18:08
eleuth wrote:
During the first 11 months of a recent year, a certain charitable organization received an average of $20,600 per month in donations. How much did the organization receive in donations during December of that year if the average amount of donations per month for the entire year was $21,000?

A. $21,400
B. $21,600
C. $24,000
D. $25,400
E. $25,800


Hello There,
Average for 11 months = 20,600
M1 + M2 + ……. + M11
------------------------------- = 20,600
11

M1 + M2 +……..+ M11 = 20,600 X 11 = 2,26,600

Average for 12 months = 21,000
M1 + M2 + ……. + M11 + M12
----------------------------------------- = 21,000
12

(M1 + M2 +……..+ M11) + M12 = 21,000 X 12
2,26,600 + M12 = 2,52,000
M12 = 2,52,000 – 2,26,600 = 25,400
_________________

Regards,
Bharat Bhushan Sunkara.


"You need to sacrifice what you are TODAY, for what you want to be TOMORROW!!"

Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8199
Location: Pune, India
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 20 Oct 2014, 20:31
bharatS wrote:
eleuth wrote:
During the first 11 months of a recent year, a certain charitable organization received an average of $20,600 per month in donations. How much did the organization receive in donations during December of that year if the average amount of donations per month for the entire year was $21,000?

A. $21,400
B. $21,600
C. $24,000
D. $25,400
E. $25,800


Hello There,
Average for 11 months = 20,600
M1 + M2 + ……. + M11
------------------------------- = 20,600
11

M1 + M2 +……..+ M11 = 20,600 X 11 = 2,26,600

Average for 12 months = 21,000
M1 + M2 + ……. + M11 + M12
----------------------------------------- = 21,000
12

(M1 + M2 +……..+ M11) + M12 = 21,000 X 12
2,26,600 + M12 = 2,52,000
M12 = 2,52,000 – 2,26,600 = 25,400


Your method is correct but it involves quite a bit of calculations. The method used by Bunuel above is much more crisp. This method is discussed in detail here: http://www.veritasprep.com/blog/2012/04 ... etic-mean/
Check it out.
_________________

Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >

GMAT self-study has never been more personalized or more fun. Try ORION Free!

Intern
Intern
User avatar
Joined: 13 Jul 2014
Posts: 10
Location: India
Concentration: Operations, Technology
GMAT Date: 11-06-2014
GRE 1: Q159 V144
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 20 Oct 2014, 21:54
VeritasPrepKarishma wrote:
bharatS wrote:
eleuth wrote:
During the first 11 months of a recent year, a certain charitable organization received an average of $20,600 per month in donations. How much did the organization receive in donations during December of that year if the average amount of donations per month for the entire year was $21,000?

A. $21,400
B. $21,600
C. $24,000
D. $25,400
E. $25,800


Hello There,
Average for 11 months = 20,600
M1 + M2 + ……. + M11
------------------------------- = 20,600
11

M1 + M2 +……..+ M11 = 20,600 X 11 = 2,26,600

Average for 12 months = 21,000
M1 + M2 + ……. + M11 + M12
----------------------------------------- = 21,000
12

(M1 + M2 +……..+ M11) + M12 = 21,000 X 12
2,26,600 + M12 = 2,52,000
M12 = 2,52,000 – 2,26,600 = 25,400


Your method is correct but it involves quite a bit of calculations. The method used by Bunuel above is much more crisp. This method is discussed in detail here: http://www.veritasprep.com/blog/2012/04 ... etic-mean/
Check it out.


Hello There,
Ya, was just trying to explain the concept. Surely will follow Bunuel. Thanks for your inputs.
_________________

Regards,
Bharat Bhushan Sunkara.


"You need to sacrifice what you are TODAY, for what you want to be TOMORROW!!"

Senior Manager
Senior Manager
User avatar
Status: Math is psycho-logical
Joined: 07 Apr 2014
Posts: 421
Location: Netherlands
GMAT Date: 02-11-2015
WE: Psychology and Counseling (Other)
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 15 Jan 2015, 10:18
While I like the response by MKS, I also tried to do it another way and it doesn't work out.
Could you tell me what I am doing wrong?

So, starting by looking for the sum of the earning we have:
20600 = S/11 --> S = 226600

Then if we add the remaining earning for the last month of the year this becomes:
21000 = (226600 + x) / 12 => x = 229400, which is wrong...
EMPOWERgmat Instructor
User avatar
V
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 12217
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 15 Jan 2015, 22:29
Hi pacifist85,

Your set-up and logic are fine.

When you get to this point in the "math"....

21000 = (226600 + x) / 12

....What did you do next? (you include a value for X that was incorrect, so I don't know HOW you worked through your math).

Here is a correct series of math "steps":
21,000(12) = 252,000

252,000 = 226,600 + X
25,400 = X

Final Answer:

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

Senior Manager
Senior Manager
User avatar
Status: Math is psycho-logical
Joined: 07 Apr 2014
Posts: 421
Location: Netherlands
GMAT Date: 02-11-2015
WE: Psychology and Counseling (Other)
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 16 Jan 2015, 01:18
Hi Rich,

What I did next was to just solve for X:
21000 = (226600 + x) / 12 => x = 229400.

So, my reasoning behind this was to add the missing amount to the S ( 226600 + x ) and divide again by 12, because now we have a new day to account for ( / 12 ). And I know see that I actually get the correct answer. As 21000*12=226600+x --> 252000 = 226600 + x --> 252000 - 226600 = x --> x = 25400.

At the moment I don't know what my problem was.. Perhaps I shouldn't be GMATing for 12 hours evryday...

But, what did you mean with "What did you do next? (you include a value for X that was incorrect, so I don't know HOW you worked through your math)". Why was adding X there incorrect?

Thank you!
EMPOWERgmat Instructor
User avatar
V
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 12217
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 16 Jan 2015, 12:16
Hi pacifist85,

I was asking about how you did your calculation because you did not include that information. There was just a number (229,400) and a comment stating "...which is wrong." You got to that number somehow, but you did not explain how.

Just about every Test Taker makes some silly mistakes during practice; to keep those silly mistakes from happening AGAIN, it's important to define WHY they happened in the first place. Maybe you didn't take enough notes, maybe you did math in your head, maybe you used "math rules" incorrectly. Whatever the reason, by defining it....you should be able to fix it.

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

Senior Manager
Senior Manager
User avatar
Status: Math is psycho-logical
Joined: 07 Apr 2014
Posts: 421
Location: Netherlands
GMAT Date: 02-11-2015
WE: Psychology and Counseling (Other)
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 17 Jan 2015, 02:07
Thank you Rich. It is true that I make such silly mistakes more often than I should. Be it in mistakes is easy calculations or even copying the figures incorrectly... Not sure what is wrong there. I guess I cannot focus as much as needed!

Thank you though, because up until you told me that the solution seems correct (apart from the result of course) I was thinking that I was solving the problem incorrectly. Which was surprising since statistics is one of my strengths!
Intern
Intern
avatar
Joined: 23 Sep 2014
Posts: 36
Location: India
Concentration: Marketing, Finance
GMAT 1: 670 Q48 V34
GMAT ToolKit User Reviews Badge
During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 01 Dec 2016, 08:06
Hi Bunuel VeritasPrepKarishma,

I was reviewing the GMATPrep mock I gave today, I scored a Q48 with 7 incorrect, with last 17 Q's correct.

This particular question came as Q28( The difficulty level mentioned here is sub 600), and Q27 that came in the mock has a difficulty level of 700+ on GMAT Club, are the GMAT prep test not adaptive? or is the same fluctuation in the difficulty level of the Q can be expected in the Exam?

I am a retaker, have Q46 and Q44 in my previous two attempts, so needed to be sure, whether this is an inflated score or pretty much according to my current ability.
Exam Pack 1 :
GMAT3 (Q48,V37)
GMAT4(Q48,V39)

TIA
Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8199
Location: Pune, India
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 02 Dec 2016, 20:54
1
believer700 wrote:
Hi Bunuel VeritasPrepKarishma,

I was reviewing the GMATPrep mock I gave today, I scored a Q48 with 7 incorrect, with last 17 Q's correct.

This particular question came as Q28( The difficulty level mentioned here is sub 600), and Q27 that came in the mock has a difficulty level of 700+ on GMAT Club, are the GMAT prep test not adaptive? or is the same fluctuation in the difficulty level of the Q can be expected in the Exam?

I am a retaker, have Q46 and Q44 in my previous two attempts, so needed to be sure, whether this is an inflated score or pretty much according to my current ability.
Exam Pack 1 :
GMAT3 (Q48,V37)
GMAT4(Q48,V39)

TIA


GMAT Prep is adaptive. Some sudden variation in difficulty level could be there because the algorithm considers various aspects (other than the difficulty level) such as the topics that still need to be tested, the question format to be given etc while selecting the next question.
There is no reason for the score to be inflated.
_________________

Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >

GMAT self-study has never been more personalized or more fun. Try ORION Free!

Intern
Intern
avatar
Joined: 23 Sep 2014
Posts: 36
Location: India
Concentration: Marketing, Finance
GMAT 1: 670 Q48 V34
GMAT ToolKit User Reviews Badge
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 02 Dec 2016, 21:21
VeritasPrepKarishma wrote:
believer700 wrote:
Hi Bunuel VeritasPrepKarishma,

I was reviewing the GMATPrep mock I gave today, I scored a Q48 with 7 incorrect, with last 17 Q's correct.

This particular question came as Q28( The difficulty level mentioned here is sub 600), and Q27 that came in the mock has a difficulty level of 700+ on GMAT Club, are the GMAT prep test not adaptive? or is the same fluctuation in the difficulty level of the Q can be expected in the Exam?

I am a retaker, have Q46 and Q44 in my previous two attempts, so needed to be sure, whether this is an inflated score or pretty much according to my current ability.
Exam Pack 1 :
GMAT3 (Q48,V37)
GMAT4(Q48,V39)

TIA


GMAT Prep is adaptive. Some sudden variation in difficulty level could be there because the algorithm considers various aspects (other than the difficulty level) such as the topics that still need to be tested, the question format to be given etc while selecting the next question.
There is no reason for the score to be inflated.


This helps a lot.

Many thanks :-D
Manager
Manager
avatar
B
Joined: 26 Mar 2017
Posts: 145
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 15 Jun 2017, 11:59
MKS wrote:
Say for December month, It is X

then
\(11*(20600) + X = 12 * (21000)\)
=> x = 25400 - Option D



well I spent way too much time trying to find a way avoiding the long multiplication :(
_________________

I hate long and complicated explanations!

Intern
Intern
avatar
B
Joined: 18 Jan 2017
Posts: 40
Re: During the first 11 months of a recent year, a certain charitable orga  [#permalink]

Show Tags

New post 11 Dec 2017, 17:43
jadon wrote:
During the first 11 months of a recent year, a certain charitable organization received an average of $20,600 per month in donations. How much did the organization receive in donations during December of that year if the average amount of donations per month for the entire year was $21,000?

A. $21,400
B. $21,600
C. $24,000
D. $25,400
E. $25,800



average for 11 months = 20,600
20,600= x/11
x=226,600

average for the year= 21,000
21,000=x/12
x=252,000

252,000-226,600= 25,400
Re: During the first 11 months of a recent year, a certain charitable orga &nbs [#permalink] 11 Dec 2017, 17:43
Display posts from previous: Sort by

During the first 11 months of a recent year, a certain charitable orga

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

Events & Promotions

PREV
NEXT


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®.