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

 It is currently 22 Oct 2019, 20:34

### 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

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

# If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58427
If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

18 Jan 2018, 03:23
00:00

Difficulty:

15% (low)

Question Stats:

84% (01:23) correct 16% (01:43) wrong based on 185 sessions

### HideShow timer Statistics

If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what is the average of m + 4 and n – 2 ?

(A) 9
(B) 13
(C) 14
(D) 18
(E) 26

_________________
Manager
Joined: 16 Jan 2018
Posts: 89
Location: New Zealand
Re: If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

18 Jan 2018, 03:29
(3+6+10+m+n)/5 = 9
Solving we get m+n = 26

(m+4+n-2)/2 = (m+n+2)/2 = 28/2 = 14.
Option C.

Sent from my ONE E1003 using GMAT Club Forum mobile app
Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4774
Location: India
GPA: 3.5
Re: If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

18 Jan 2018, 07:45
Bunuel wrote:
If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what is the average of m + 4 and n – 2 ?

(A) 9
(B) 13
(C) 14
(D) 18
(E) 26

3 + 6 + 10 + m + n = 45

Or, ( m + n ) + 19 = 45

Or, m + n = 26

Now, the average of m + 4 and n – 2 is

= $$\frac{(m + n ) + 4 - 2}{2}$$

= $$\frac{28}{2}$$

= $$14$$, Answer will be (C)
_________________
Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )
Senior PS Moderator
Joined: 26 Feb 2016
Posts: 3333
Location: India
GPA: 3.12
If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

18 Jan 2018, 08:41
Bunuel wrote:
If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what is the average of m + 4 and n – 2 ?

(A) 9
(B) 13
(C) 14
(D) 18
(E) 26

Average of m+4 and n-2 is $$\frac{m+n+4-2}{2} = \frac{m+n}{2} + 1$$ = Average of m,n + 1

It has been given that the average of 5 numbers is 9, making their sum 45.
Of the 5 numbers, we know that three of the numbers total 19. So, m+n=26
Average of m and n is 13.

Therefore, the average of m+4 and n-2 is 13+1 = 14(Option C)
_________________
You've got what it takes, but it will take everything you've got
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8137
Location: United States (CA)
Re: If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

20 Jan 2018, 07:39
Bunuel wrote:
If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what is the average of m + 4 and n – 2 ?

(A) 9
(B) 13
(C) 14
(D) 18
(E) 26

We can use the formula for the arithmetic mean to create the equation:

(3 + 6 + 10 + m + n)/5 = 9

19 + m + n = 45

m + n = 26

We need to determine the average of m + 4 and n – 2; thus:

(m + 4 + n - 2)/2 = (m + n + 4 - 2)/2 = (26 + 4 - 2)/2 = 28/2 = 14

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Intern
Joined: 28 Dec 2017
Posts: 30
Re: If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

20 Jan 2018, 12:54
Find average of 3, 6, 10, m and n first.
(3+6+10+m+n)/5 = 9
Simplify the equation:
3+6+10+m+n = 45
m+n = 26

Problem is asking for average of (m+4) and (n-2):
[(m+4)+(n-2)]/2 = ?
(m+n+2)/2 = ?
Substituting m+n into the equation, (26+2)/2 = 14 (Option C)
Manager
Joined: 21 Aug 2017
Posts: 77
Location: United States
Schools: Oxford"20 (A)
GMAT 1: 700 Q43 V42
Re: If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

20 Feb 2018, 19:15
Bunuel wrote:
If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what is the average of m + 4 and n – 2 ?

(A) 9
(B) 13
(C) 14
(D) 18
(E) 26

This question would be absolutely punishing if 7 were an answer choice.
SVP
Joined: 26 Mar 2013
Posts: 2343
Re: If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

20 Feb 2018, 20:21
Bunuel wrote:
If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what is the average of m + 4 and n – 2 ?

(A) 9
(B) 13
(C) 14
(D) 18
(E) 26

$$\frac{3+6+10+m+n}{5}$$ = 9

19 + m +n = 45...........m+n = 26 & m++4+n-2 = m +n +2 = 28

Average = $$\frac{28}{2}$$ =14

Intern
Joined: 20 Feb 2018
Posts: 2
Re: If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

20 Feb 2018, 20:41
[{(9-3)+(9-6)+(9-10)+4-2}/2]+9

Sent from my SM-J710F using GMAT Club Forum mobile app
Intern
Joined: 20 Feb 2018
Posts: 2
Re: If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

20 Feb 2018, 20:47
3 is 6 less than 9(average) & 6 is 3 less and 10 is 1 more so we got 8 less that has to be covered by m and n so average of m and n is 9+(8/2)= 13 and then m+4 and n-2 we have 2 as extra other than m &n and by dividing it with 2 we get 1 which is added to average of m & n so final answer is 14

Sent from my SM-J710F using GMAT Club Forum mobile app
GMAT Club Legend
Joined: 12 Sep 2015
Posts: 4018
Re: If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what  [#permalink]

### Show Tags

09 Mar 2018, 08:33
Top Contributor
Bunuel wrote:
If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what is the average of m + 4 and n – 2 ?

(A) 9
(B) 13
(C) 14
(D) 18
(E) 26

The average (arithmetic mean) of 3, 6, 10, m and n is 9
So, (3 + 6 + 10 + m + n)/5 = 9
Multiply both sides by 5 to get: 3 + 6 + 10 + m + n = 45
Simplify: 19 + m + n = 45
Subtract 19 from both sides to get: m + n = 26

What is the average of m + 4 and n – 2 ?
We get: average = [(m + 4) + (n - 2)]/2
Simplify: average = (m + n + 2)/2
Replace m + n to get: average = (26 + 2)/2
Simplify: average = (28)/2 = 14

RELATED VIDEO FROM OUR COURSE

_________________
Test confidently with gmatprepnow.com
Re: If the average (arithmetic mean) of 3, 6, 10, m and n is 9, then what   [#permalink] 09 Mar 2018, 08:33
Display posts from previous: Sort by