It is currently 26 Oct 2020, 02:46
My Tests

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.

The average (arithmetic mean) of the 11 numbers in a list is

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
2 KUDOS received
Founder
Founder
User avatar
Joined: 18 Apr 2015
Posts: 13685
Followers: 305

Kudos [?]: 3535 [2] , given: 12628

CAT Tests
The average (arithmetic mean) of the 11 numbers in a list is [#permalink] New post 06 Mar 2018, 15:39
2
This post received
KUDOS
Expert's post
00:00

Question Stats:

93% (01:16) correct 6% (01:27) wrong based on 73 sessions


The average (arithmetic mean) of the 11 numbers in a list is 14. If the average of 9 of the numbers in the list is 9, what is the average of the other 2 numbers?

enter your value

[Reveal] Spoiler: OA
36.5


kudos to the right explanation and solution
_________________

- Do you want all the GRE Prep Club resources at a glance (sort of ) ?? Look at GRE Prep Club Official LinkTree page
- Do you want all the GRE Prep Club FREE resources in one spot ?? Look at Free GRE Materials - Where to get it!! (2020)
- Do you want all the FREE GRE tests on earth ?? Look at FREE GRE Practice Tests [Collection] - New Edition (2021)
- Do you want to know the GRE score in the Top 25 BS in 7 continents ?? Look at here The GRE average score at Top 25 Business Schools 2020 Ed.
- Need Practice 20 Free GRE Quant Tests available for free with 20 Kudos
- GRE Prep Club Members of the Month: Each member of the month will get three months free access of GRE Prep Club tests.

2 KUDOS received
Sherpa Prep Representative
User avatar
Joined: 15 Jan 2018
Posts: 147
GMAT 1: Q V
Followers: 7

Kudos [?]: 246 [2] , given: 0

Re: The average (arithmetic mean) of the 11 numbers in a list is [#permalink] New post 06 Mar 2018, 19:17
2
This post received
KUDOS
Expert's post
There are a few ways to do this. Here's one:

Call the total of the 9 numbers N. Since we know the 9 numbers average 9, we can use the average equation [(Sum)/(# of items)=(Avg)]. So:

N/9 = 9

and thus we know that N = 81. If we call the total of the two numbers T, we can make an equation out of the first sentence in the question:

(N + T)/11 = 14

So N + T = 154

Since we know N is 81, then T = 154 - 81, so T is 73.

Since T is actually 2 numbers, we should divide 73 by 2 to get the average, which is 36.5.
_________________

-
-
-
-
-

Need help with GRE math? Check out our ground-breaking books and app.

1 KUDOS received
GRE Instructor
User avatar
Joined: 10 Apr 2015
Posts: 3871
Followers: 158

Kudos [?]: 4649 [1] , given: 70

Re: The average (arithmetic mean) of the 11 numbers in a list is [#permalink] New post 04 May 2018, 09:31
1
This post received
KUDOS
Expert's post
Carcass wrote:
The average (arithmetic mean) of the 11 numbers in a list is 14. If the average of 9 of the numbers in the list is 9, what is the average of the other 2 numbers?

enter your value


Let's assign some variables:
Let a, b, c, d, e, f, g, h, i, j, k be the ORIGINAL 11 numbers.


The average (arithmetic mean) of the 11 numbers in a list is 14.
So, we can write: (a+b+c+d+e+f+g+h+i+j+k)/11 = 14
Multiply both sides by 11 to get: So, a+b+c+d+e+f+g+h+i+j+k = 154

If the average of 9 of the numbers in the list is 9 . . .
So, we can write: (a+b+c+d+e+f+g+h+i)/9 = 9
Multiply both sides by 9 to get: So, a+b+c+d+e+f+g+h+i = 81

. . . what is the average of the other 2 numbers?
We now have the following system:
a+b+c+d+e+f+g+h+i+j+k = 154
a+b+c+d+e+f+g+h+i = 81

Subtract the bottom equation by the top equation to get: j + k = 73
So, the AVERAGE of j and k = (j + k)/2
= 73/2
= 36.5

Answer: 36.5

RELATED VIDEO FROM OUR COURSE

_________________

Brent Hanneson – Creator of greenlighttestprep.com
If you enjoy my solutions, you'll like my GRE prep course.
Image
Sign up for GRE Question of the Day emails

Re: The average (arithmetic mean) of the 11 numbers in a list is   [#permalink] 04 May 2018, 09:31
Display posts from previous: Sort by

The average (arithmetic mean) of the 11 numbers in a list is

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GRE Prep Club Forum Home| About| Terms and Conditions and Privacy Policy| GRE Prep Club Rules| Contact

Powered by phpBB © phpBB Group

Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.