Last visit was: 18 May 2026, 00:04 It is currently 18 May 2026, 00:04
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
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 18 May 2026
Posts: 110,573
Own Kudos:
Given Kudos: 106,290
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 110,573
Kudos: 815,459
 [20]
Kudos
Add Kudos
20
Bookmarks
Bookmark this Post
User avatar
GMATinsight
User avatar
Major Poster
Joined: 08 Jul 2010
Last visit: 17 May 2026
Posts: 7,029
Own Kudos:
17,003
 [2]
Given Kudos: 128
Status:GMAT/GRE Tutor l Admission Consultant l On-Demand Course creator
Location: India
GMAT: QUANT+DI EXPERT
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
WE:Education (Education)
Products:
Expert
Expert reply
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
Posts: 7,029
Kudos: 17,003
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
Regor60
Joined: 21 Nov 2021
Last visit: 17 May 2026
Posts: 533
Own Kudos:
423
 [3]
Given Kudos: 465
Posts: 533
Kudos: 423
 [3]
2
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
User avatar
sayan640
Joined: 29 Oct 2015
Last visit: 17 May 2026
Posts: 1,110
Own Kudos:
Given Kudos: 790
GMAT 1: 570 Q42 V28
Products:
GMAT 1: 570 Q42 V28
Posts: 1,110
Kudos: 872
Kudos
Add Kudos
Bookmarks
Bookmark this Post
MartyMurray KarishmaB Would you like to explain this question ?
User avatar
chetan2u
User avatar
GMAT Expert
Joined: 02 Aug 2009
Last visit: 17 May 2026
Posts: 11,239
Own Kudos:
45,199
 [1]
Given Kudos: 337
Status:Math and DI Expert
Location: India
Concentration: Human Resources, General Management
GMAT Focus 1: 735 Q90 V89 DI81
Products:
Expert
Expert reply
GMAT Focus 1: 735 Q90 V89 DI81
Posts: 11,239
Kudos: 45,199
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
List A consists of four numbers. The smallest possible average (arithmetic mean) of three of these four numbers is 30 and the largest possible average (arithmetic mean) of three of these four numbers is 40. What is the range of possible averages of list A?

A. 2
B. 3
C. 5
D. 6
E. 10


Are You Up For the Challenge: 700 Level Questions
­sayan640, refer your PM

We have numbers, a, b, c and d.
Now, sum of the lower three or upper three is fixed. We can manipulate the values to increase or decrease the overall mean.

Let us work on the upper three => b+c+d = 3*40 = 120
a would depend on what we take b and c as.

Maximize the mean/sum: a should be the maximum, and that will be possible only when a=b=c=30 as 30 is the average of these three numbers.
so, Sum = a+b+c+d = 30+120 = 150..............a,b,c,d = 30,30,30,60

Minimize the mean/sum: a should be the minimum, and that will be possible only when b and c are maximized, that is b=c=d=40 as 40 is the average of these three numbers. Thus, a+40+40 = 3*30 = 90 or a=10
so, Sum = a+b+c+d = 10+120 = 130..............a,b,c,d = 10,30,30,60

Range of mean = \(\frac{150}{4}-\frac{130}{4}=\frac{20}{4}=5\)
 
User avatar
sayan640
Joined: 29 Oct 2015
Last visit: 17 May 2026
Posts: 1,110
Own Kudos:
Given Kudos: 790
GMAT 1: 570 Q42 V28
Products:
GMAT 1: 570 Q42 V28
Posts: 1,110
Kudos: 872
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think there is a typo.It would be 10 , 40 , 40 40.Kindly check the highlighted part.
chetan2u
Bunuel
List A consists of four numbers. The smallest possible average (arithmetic mean) of three of these four numbers is 30 and the largest possible average (arithmetic mean) of three of these four numbers is 40. What is the range of possible averages of list A?

A. 2
B. 3
C. 5
D. 6
E. 10


Are You Up For the Challenge: 700 Level Questions
­sayan640, refer your PM

We have numbers, a, b, c and d.
Now, sum of the lower three or upper three is fixed. We can manipulate the values to increase or decrease the overall mean.

Let us work on the upper three => b+c+d = 3*40 = 120
a would depend on what we take b and c as.

Maximize the mean/sum: a should be the maximum, and that will be possible only when a=b=c=30 as 30 is the average of these three numbers.
so, Sum = a+b+c+d = 30+120 = 150..............a,b,c,d = 30,30,30,60

Minimize the mean/sum: a should be the minimum, and that will be possible only when b and c are maximized, that is b=c=d=40 as 40 is the average of these three numbers. Thus, a+40+40 = 3*30 = 90 or a=10
so, Sum = a+b+c+d = 10+120 = 130..............a,b,c,d = 10,30,30,60

Range of mean = \(\frac{150}{4}-\frac{130}{4}=\frac{20}{4}=5\)
 

Posted from my mobile device
User avatar
KarishmaB
Joined: 16 Oct 2010
Last visit: 13 May 2026
Posts: 16,465
Own Kudos:
79,643
 [1]
Given Kudos: 485
Location: Pune, India
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 16,465
Kudos: 79,643
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
 
Bunuel
List A consists of four numbers. The smallest possible average (arithmetic mean) of three of these four numbers is 30 and the largest possible average (arithmetic mean) of three of these four numbers is 40. What is the range of possible averages of list A?

A. 2
B. 3
C. 5
D. 6
E. 10


Are You Up For the Challenge: 700 Level Questions
­
Let's put 4 numbers in ascending order to get: Least, B, C, Greatest

We get the smallest possible average of 3 numbers when we pick the 3 smallest numbers. So
\((Least + B + C) = 3*30 = 90\)

We get the greatest possible average of 3 numbers when we pick the 3 greatest numbers. So
\((B + C + Greatest) = 3*40 = 120\)

Average of all 4 numbers = \(\frac{90 + 120 - (B+C)}{4}\)

The smallest value of this average is when B+C is greatest. The greatest values  they can take is 40 each in which case the Greatest number is 40 too. If B and C are more than 40, then the average of greatest 3 numbers will be more than 40 too. 
Least Average of all 4 numbers = \(\frac{90 + 120 - 80}{4} = \frac{130}{4}\)

The greatest value of this average is when B+C is smallest. The smallest values  they can take is 30 each in which case the Least number is 30 too. If B and C are less than 30, then the average of smallest 3 numbers will be less than 30 too. 
Greatest Average of all 4 numbers = \(\frac{90 + 120 - 60}{4} = \frac{150}{4}\)

\(Range = \frac{150}{4} - \frac{130}{4} = 5\)

 ­Answer (C)­

Mean has been discussed here: https://youtu.be/W-qhIZ29UIs
 
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 39,088
Own Kudos:
Posts: 39,088
Kudos: 1,125
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:
Math Expert
110573 posts
Tuck School Moderator
852 posts