Last visit was: 24 Apr 2026, 23:02 It is currently 24 Apr 2026, 23:02
Home
Messages
Tests
Schools
Events
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 Apr 2026
Posts: 109,818
Own Kudos:
811,094
 [9]
Given Kudos: 105,873
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,818
Kudos: 811,094
 [9]
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 01 Apr 2015, 03:49
2
Kudos
Add Kudos
6
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

15% (low)

Question Stats:

77% (01:19) correct 23% (01:17) wrong based on 393 sessions

History

Date
Time
Result
Not Attempted Yet
The average (arithmetic mean) of five numbers is 3x + 4. If one of the numbers is 7x - 4, what is the average of the other four numbers?

A. 1.6x + 3.2
B. 1.6x + 4.8
C. 2x + 4
D. 2x + 6
E. 4x + 8
ShowHide Answer
Official Answer
D
User avatar
TARGET730
User avatar
Joined: 10 Sep 2014
Last visit: 06 Aug 2021
Posts: 57
Own Kudos:
293
 [1]
Given Kudos: 102
Schools: LBS '17 Insead Sept '16
Schools: LBS '17 Insead Sept '16
Posts: 57
Kudos: 293
 [1]
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 01 Apr 2015, 03:54
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The answer is 2x + 6, which is not given in the answer choices
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 Apr 2026
Posts: 109,818
Own Kudos:
811,094
Given Kudos: 105,873
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,818
Kudos: 811,094
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 01 Apr 2015, 03:55
Kudos
Add Kudos
Bookmarks
Bookmark this Post
TARGET730
The answer is 2x + 6, which is not given in the answer choices
Show more
__________
Edited. Thank you.
avatar
sharma123
avatar
Joined: 29 Oct 2014
Last visit: 03 May 2017
Posts: 31
Own Kudos:
23
Given Kudos: 194
Products:
My Reviews
Posts: 31
Kudos: 23
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 01 Apr 2015, 04:38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
TARGET730
The answer is 2x + 6, which is not given in the answer choices
Show more
can u please explain how you got 2x+6 as the answer.
im getting (2x+4)
User avatar
onedayill
User avatar
Joined: 25 Feb 2010
Last visit: 08 Mar 2017
Posts: 207
Own Kudos:
341
 [2]
Given Kudos: 10
Posts: 207
Kudos: 341
 [2]
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 01 Apr 2015, 05:02
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
7x-4 + y (all four numbers) / 5 = 3x+4

7x-4 +y = 15x+20

y = 8x+24

Avg. of 4 numbers = 2x+6.
avatar
SavageBrother
avatar
Joined: 18 Dec 2014
Last visit: 03 Oct 2015
Posts: 95
Own Kudos:
51
Given Kudos: 5
Posts: 95
Kudos: 51
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 01 Apr 2015, 06:11
Kudos
Add Kudos
Bookmarks
Bookmark this Post
This is what I did;

5 numbers, average of 5 numbers = 3x+4
5*(3x+4) = 15x + 20
15x + 20 - 7x - 4= 8x + 16

8x + 16 / 4 = 2x + 4.

What did I do wrong?
User avatar
Turkish
User avatar
Joined: 13 Jun 2012
Last visit: 09 Apr 2023
Posts: 164
Own Kudos:
623
Given Kudos: 467
Location: United States
WE:Supply Chain Management (Computer Hardware)
Posts: 164
Kudos: 623
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 01 Apr 2015, 15:52
Kudos
Add Kudos
Bookmarks
Bookmark this Post
SavageBrother
This is what I did;

5 numbers, average of 5 numbers = 3x+4
5*(3x+4) = 15x + 20
15x + 20 - 7x - 4= 8x + 16

8x + 16 / 4 = 2x + 4.

What did I do wrong?
Show more

You forgot the minus buddy! 15x + 20 - (7x - 4)= 8x + 24 / 4 is the answer!
avatar
PareshGmat
avatar
Joined: 27 Dec 2012
Last visit: 10 Jul 2016
Posts: 1,531
Own Kudos:
8,274
Given Kudos: 193
Status:The Best Or Nothing
Location: India
Concentration: General Management, Technology
WE:Information Technology (Computer Software)
Posts: 1,531
Kudos: 8,274
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 01 Apr 2015, 23:16
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Answer = D. 2x + 6

Let the addition of other 4 numbers = a; we require to find \(\frac{a}{4}\)

\(\frac{a + 7x-4}{5} = 3x+4\)

a = 8x+24

\(\frac{a}{4} = 2x+6\)
avatar
aj13783
avatar
Joined: 22 Aug 2014
Last visit: 25 Aug 2018
Posts: 29
Own Kudos:
42
 [1]
Given Kudos: 6
Posts: 29
Kudos: 42
 [1]
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 02 Apr 2015, 02:13
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
The average (arithmetic mean) of five numbers is 3x + 4. If one of the numbers is 7x - 4, what is the average of the other four numbers?

A. 1.6x + 3.2
B. 1.6x + 4.8
C. 2x + 4
D. 2x + 6
E. 4x + 8


Kudos for a correct solution.
Show more

Sum(5 nos)/5 = 3x + 4
Sum(7x-4 + 4 nos) = 15x + 20
Sum( 4 nos) = 8x + 24
AM(4 nos) = 2x + 6

Option D
avatar
aj13783
avatar
Joined: 22 Aug 2014
Last visit: 25 Aug 2018
Posts: 29
Own Kudos:
42
 [1]
Given Kudos: 6
Posts: 29
Kudos: 42
 [1]
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 02 Apr 2015, 02:13
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
The average (arithmetic mean) of five numbers is 3x + 4. If one of the numbers is 7x - 4, what is the average of the other four numbers?

A. 1.6x + 3.2
B. 1.6x + 4.8
C. 2x + 4
D. 2x + 6
E. 4x + 8


Kudos for a correct solution.
Show more

Sum(5 nos)/5 = 3x + 4
Sum(7x-4 + 4 nos) = 15x + 20
Sum( 4 nos) = 8x + 24
AM(4 nos) = 2x + 6

Option D
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 Apr 2026
Posts: 109,818
Own Kudos:
811,094
 [1]
Given Kudos: 105,873
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,818
Kudos: 811,094
 [1]
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 06 Apr 2015, 05:57
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
The average (arithmetic mean) of five numbers is 3x + 4. If one of the numbers is 7x - 4, what is the average of the other four numbers?

A. 1.6x + 3.2
B. 1.6x + 4.8
C. 2x + 4
D. 2x + 6
E. 4x + 8


Kudos for a correct solution.
Show more

MAGOOSH OFFICIAL SOLUTION:
Attachment:
averageis3xplus4_text.PNG
averageis3xplus4_text.PNG [ 18.42 KiB | Viewed 11317 times ]
User avatar
stonecold
User avatar
Joined: 12 Aug 2015
Last visit: 09 Apr 2024
Posts: 2,231
Own Kudos:
3,643
Given Kudos: 893
Schools: Boston U '20 (M)
GRE 1: Q169 V154
Schools: Boston U '20 (M)
GRE 1: Q169 V154
Posts: 2,231
Kudos: 3,643
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 10 Dec 2016, 08:32
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Here is my solution to this one -->
Sum(5)=> 15x+20
Sum(4)=> 15x+20-(7x-4) => 8x+24
Hence Mean of 4 numbers -> 2x+6

Hence D
User avatar
EgmatQuantExpert
User avatar
e-GMAT Representative
Joined: 04 Jan 2015
Last visit: 02 Apr 2024
Posts: 3,657
Own Kudos:
20,880
Given Kudos: 165
Expert
Expert reply
Posts: 3,657
Kudos: 20,880
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 25 Nov 2019, 20:30
Kudos
Add Kudos
Bookmarks
Bookmark this Post

Solution



Given
    • The average (arithmetic mean) of five numbers is 3x + 4
    • one of the numbers is 7x – 4.

To find
    • The average of the other four numbers.

Approach and Working out

    • Average of 5 numbers = 3x +4
      o Sum of numbers / 5 = 3x+4
    • One of the numbers = 7x-4
      o 7x -4 + sum of remaining 4 numbers / 5 = 3x + 4
      o 7x -4 + sum of remaining 4 numbers = 15x + 20
      o Sum of remaining 4 numbers = 8x + 24
    • Average of remaining 4 numbers = 8x +24 /4 = 2x +6
Thus, option D is the correct answer.
Correct Answer: Option D
avatar
am12k
avatar
Joined: 02 Nov 2019
Last visit: 10 Aug 2020
Posts: 9
Own Kudos:
2
Given Kudos: 10
Posts: 9
Kudos: 2
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 15 Dec 2019, 15:42
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The total of the five numbers is \(5*(3x+4)=15x+20\)
One of the numbers is \(7x-4\). Therefore, \(15x+20=(7x-4)+a+b+c+d\)
and \(8x+24=a+b+c+d\)
So the average of the other four numbers (a, b, c, d) is \(\frac{(8x+24)}{4}=2x+6\) (Answer D)
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 24 Apr 2026
Posts: 22,286
Own Kudos:
26,534
Given Kudos: 302
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 22,286
Kudos: 26,534
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 08 Nov 2022, 18:10
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
The average (arithmetic mean) of five numbers is 3x + 4. If one of the numbers is 7x - 4, what is the average of the other four numbers?

A. 1.6x + 3.2
B. 1.6x + 4.8
C. 2x + 4
D. 2x + 6
E. 4x + 8


Kudos for a correct solution.
Show more

Remember that average = sum / quantity. Since the average of the five numbers is 3x + 4, the sum of these five numbers is 5 * (3x + 4) = 15x + 20. We are told that one of the numbers is 7x - 4, thus the sum of the remaining four numbers is 15x + 20 - (7x - 4) = 15x + 20 - 7x + 4 = 8x + 24. Since the sum of the four numbers besides 7x - 4 is 8x + 24, the average of these four numbers is (8x + 24)/4 = 8x/4 + 24/4 = 2x + 6.

Answer: D
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,978
Own Kudos:
1,117
Posts: 38,978
Kudos: 1,117
The average (arithmetic mean) of five numbers is 3x + 4. If one of the 16 Apr 2025, 11:21
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.
Moderators:
Bunuel
Math Expert
109818 posts
Krunaal
Tuck School Moderator
853 posts