Last visit was: 24 Apr 2026, 07:03 It is currently 24 Apr 2026, 07:03
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
505-555 (Easy)|   Arithmetic|      
User avatar
cfc198
User avatar
CAT Forum Moderator
Joined: 29 Nov 2018
Last visit: 12 Apr 2020
Posts: 261
Own Kudos:
832
 [6]
Given Kudos: 50
Concentration: Marketing, Strategy
Posts: 261
Kudos: 832
 [6]
Ten years ago, the average age of a couple was 27 years old. Today 07 Jan 2019, 11:06
Kudos
Add Kudos
6
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
E
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:

86% (01:44) correct 14% (02:15) wrong based on 194 sessions

History

Date
Time
Result
Not Attempted Yet
Ten years ago, the average age of a couple was 27 years old. Today also the average age of the couple and their baby is 27 years old. Find the present age of the baby.

A 4
B 3
C 2
D 5
E 7
ShowHide Answer
Official Answer
E
User avatar
KanishkM
User avatar
Joined: 09 Mar 2018
Last visit: 18 Dec 2021
Posts: 755
Own Kudos:
512
 [2]
Given Kudos: 123
Location: India
Schools: DeGroote'21 Desautels '21 NUS '21
Schools: DeGroote'21 Desautels '21 NUS '21
Posts: 755
Kudos: 512
 [2]
Ten years ago, the average age of a couple was 27 years old. Today 07 Jan 2019, 11:30
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
cfc198
Ten years ago, the average age of a couple was 27 years old. Today also the average age of the couple and their baby is 27 years old. Find the present age of the baby.

A 4
B 3
C 2
D 5
E 7
Show more

Couple's age = x+y, Baby's age = z

Ten years Ago,
\(\frac{x+y}{2}\)- 10 =27
x+y-20 = 54
x+y =74

\(\frac{x+y+z}{3}\) =27
x+y+z = 81
z = 7

Correct Answer E
User avatar
mangamma
User avatar
Joined: 25 Dec 2018
Last visit: 12 Jul 2023
Posts: 505
Own Kudos:
1,872
 [1]
Given Kudos: 994
Location: India
Concentration: General Management, Finance
GMAT Date: 02-18-2019
GPA: 3.4
WE:Engineering (Consulting)
Posts: 505
Kudos: 1,872
 [1]
Ten years ago, the average age of a couple was 27 years old. Today 09 Jan 2019, 02:02
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
cfc198
Ten years ago, the average age of a couple was 27 years old. Today also the average age of the couple and their baby is 27 years old. Find the present age of the baby.

A 4
B 3
C 2
D 5
E 7
Show more

Couple's age = x+y, Baby's age = z

Ten years Ago,
x+y =27 * 2
x+y= 54

after 10 years

(x+10)+(y+10)+z =27 * 3
x+y+z = 81
z = 7

Correct Answer E
User avatar
anshkool4u
User avatar
Current Student
Joined: 18 Oct 2018
Last visit: 22 Oct 2022
Posts: 91
Own Kudos:
74
Given Kudos: 23
Location: India
Concentration: Finance, Operations
Schools: IIMA PGPX'23 (A)
GMAT 1: 710 Q50 V36
GPA: 4
WE:Business Development (Retail Banking)
Schools: IIMA PGPX'23 (A)
GMAT 1: 710 Q50 V36
Posts: 91
Kudos: 74
Ten years ago, the average age of a couple was 27 years old. Today 09 Jan 2019, 11:44
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Sum of age of parents,10 years ago= 27*2=54
Therefore, some of age of parents today= 54+10+10 =74 (adding 10 years to the age of both of the parent)
But today, age of parents and child average to 27 years.
So, sum of the ages of the three,today=27*3=81
Thus, age of child= age of all three-age of parents= 81-74=7

Hence, E
User avatar
KarishmaB
User avatar
Joined: 16 Oct 2010
Last visit: 23 Apr 2026
Posts: 16,442
Own Kudos:
79,401
 [2]
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: 16,442
Kudos: 79,401
 [2]
Ten years ago, the average age of a couple was 27 years old. Today 09 Jan 2019, 22:20
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
cfc198
Ten years ago, the average age of a couple was 27 years old. Today also the average age of the couple and their baby is 27 years old. Find the present age of the baby.

A 4
B 3
C 2
D 5
E 7
Show more

Use the concept of deviation to solve it in seconds.

Th average age of two people was 27 so they were effectively 27 years old each.
After 10 yrs, there was an extra 20 yrs deviation but average remained same so there must have been a shortfall of 20 too. The shortfall would come from the child's age so the child must be 27 - 20 = 7 years old.

Answer (E)
User avatar
Tatra813
User avatar
Joined: 04 May 2025
Last visit: 04 Mar 2026
Posts: 1
Given Kudos: 19
Posts: 1
Kudos: 0
Ten years ago, the average age of a couple was 27 years old. Today 05 Feb 2026, 13:07
Kudos
Add Kudos
Bookmarks
Bookmark this Post
(27 + 27) / 2 = 27

(27 + 10 + 27 + 10 + x) / 3 = 27

<=> 37 + 37 + x = 81
<=> x = 7

Never heard of a baby being 7 years old though haha.
Moderators:
Bunuel
Math Expert
109813 posts
Krunaal
Tuck School Moderator
853 posts