Last visit was: 28 Apr 2026, 17:26 It is currently 28 Apr 2026, 17:26
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: 28 Apr 2026
Posts: 109,950
Own Kudos:
811,798
 [3]
Given Kudos: 105,927
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: 109,950
Kudos: 811,798
 [3]
The average age of three people living in a house man, woman and chi 08 Apr 2022, 07:45
1
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

5% (low)

Question Stats:

91% (01:39) correct 9% (02:32) wrong based on 64 sessions

History

Date
Time
Result
Not Attempted Yet
The average age of three people living in a house – man, woman and child, is 24 years. If the man leaves and his mother stays in his place, then the average age in the house becomes 34 years. How much older is the mother than her son?

A 20
B 25
C 30
D 32
E 36
ShowHide Answer
Official Answer
C
User avatar
BrentGMATPrepNow
User avatar
Major Poster
Joined: 12 Sep 2015
Last visit: 31 Oct 2025
Posts: 6,733
Own Kudos:
36,476
 [3]
Given Kudos: 799
Location: Canada
Expert
Expert reply
Posts: 6,733
Kudos: 36,476
 [3]
The average age of three people living in a house man, woman and chi 08 Apr 2022, 07:51
3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
The average age of three people living in a house – man, woman and child, is 24 years. If the man leaves and his mother stays in his place, then the average age in the house becomes 34 years. How much older is the mother than her son?

A 20
B 25
C 30
D 32
E 36
Show more

Let M, W, and C = the ages of the man, woman, and child respectively.
Let G = the age of the man's mother.

The average age of three people living in a house – man, woman and child, is 24 years.
So, we can write: (M + W + C)/3 = 24
Multiply both sides of the equation by 3 to get: M + W + C = 72

If the man leaves and his mother stays in his place, then the average age in the house becomes 34 years.
So, we can write: (G + W + C)/3 = 34
Multiply both sides of the equation by 3 to get: G + W + C = 102

How much older is the mother than her son?
In other words, we want to find the value of G - M

We now have the following system of equations:
G + W + C = 102
M + W + C = 72

If we subtract the bottom equation from the top equation we get: G - M = 30

Answer: C
User avatar
Pigna351
User avatar
Joined: 23 Sep 2024
Last visit: 09 Mar 2025
Posts: 2
Given Kudos: 11
Posts: 2
Kudos: 0
The average age of three people living in a house man, woman and chi 17 Oct 2024, 03:19
Kudos
Add Kudos
Bookmarks
Bookmark this Post
What does the variable G stand for?
BrentGMATPrepNow
Bunuel
The average age of three people living in a house – man, woman and child, is 24 years. If the man leaves and his mother stays in his place, then the average age in the house becomes 34 years. How much older is the mother than her son?

A 20
B 25
C 30
D 32
E 36

Let M, W, and C = the ages of the man, woman, and child respectively.
Let G = the age of the man's mother.

The average age of three people living in a house – man, woman and child, is 24 years.
So, we can write: (M + W + C)/3 = 24
Multiply both sides of the equation by 3 to get: M + W + C = 72

If the man leaves and his mother stays in his place, then the average age in the house becomes 34 years.
So, we can write: (G + W + C)/3 = 34
Multiply both sides of the equation by 3 to get: G + W + C = 102

How much older is the mother than her son?
In other words, we want to find the value of G - M

We now have the following system of equations:
G + W + C = 102
M + W + C = 72

If we subtract the bottom equation from the top equation we get: G - M = 30

Answer: C
Show more
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 28 Apr 2026
Posts: 109,950
Own Kudos:
811,798
Given Kudos: 105,927
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: 109,950
Kudos: 811,798
The average age of three people living in a house man, woman and chi 17 Oct 2024, 08:56
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Pigna351
What does the variable G stand for?
BrentGMATPrepNow
Bunuel
The average age of three people living in a house – man, woman and child, is 24 years. If the man leaves and his mother stays in his place, then the average age in the house becomes 34 years. How much older is the mother than her son?

A 20
B 25
C 30
D 32
E 36

Let M, W, and C = the ages of the man, woman, and child respectively.
Let G = the age of the man's mother.

The average age of three people living in a house – man, woman and child, is 24 years.
So, we can write: (M + W + C)/3 = 24
Multiply both sides of the equation by 3 to get: M + W + C = 72

If the man leaves and his mother stays in his place, then the average age in the house becomes 34 years.
So, we can write: (G + W + C)/3 = 34
Multiply both sides of the equation by 3 to get: G + W + C = 102

How much older is the mother than her son?
In other words, we want to find the value of G - M

We now have the following system of equations:
G + W + C = 102
M + W + C = 72

If we subtract the bottom equation from the top equation we get: G - M = 30

Answer: C
Show more

G represents the age of the man's mother (the fourth person, essentially the grandmother). The question tells us that the combined age of the three original people (M, W, and C) is 72 years, and when the man (M) is replaced by his mother (G), the combined age of the three people (G, W, and C) becomes 102 years.
Moderators:
Bunuel
Math Expert
109950 posts
Krunaal
Tuck School Moderator
852 posts