Last visit was: 18 May 2026, 06:33 It is currently 18 May 2026, 06:33
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: 18 May 2026
Posts: 110,600
Own Kudos:
815,517
 [8]
Given Kudos: 106,294
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: 110,600
Kudos: 815,517
 [8]
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their 22 Oct 2020, 12:28
3
Kudos
Add Kudos
5
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

35% (medium)

Question Stats:

74% (02:12) correct 26% (02:02) wrong based on 196 sessions

History

Date
Time
Result
Not Attempted Yet
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their squares is 1368, what is the value of the first number?

A. 6
B. 12
C. 18
D. 24
E. 30
ShowHide Answer
Official Answer
B
User avatar
nick1816
User avatar
Retired Moderator
Joined: 19 Oct 2018
Last visit: 12 Mar 2026
Posts: 1,841
Own Kudos:
8,552
Given Kudos: 707
Location: India
Posts: 1,841
Kudos: 8,552
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their 22 Oct 2020, 16:05
Kudos
Add Kudos
Bookmarks
Bookmark this Post
4x^2+9x^2+25x^2 = 1368

38x^2 = 1368

x^2 = 36

x=6

first number = 2*6=12

Bunuel
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their squares is 1368, what is the value of the first number?

A. 6
B. 12
C. 18
D. 24
E. 30
Show more
User avatar
gmatcafe
User avatar
Joined: 27 Sep 2020
Last visit: 25 Nov 2022
Posts: 182
Own Kudos:
289
Given Kudos: 97
Location: Uzbekistan
Concentration: Finance, Strategy
Schools: Marshall '25 Smeal Carey Ross '25
GPA: 3.73
WE:Consulting (Consulting)
Schools: Marshall '25 Smeal Carey Ross '25
Posts: 182
Kudos: 289
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their 22 Oct 2020, 20:16
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their squares is 1368, what is the value of the first number?

A. 6
B. 12
C. 18
D. 24
E. 30
Show more

Let x be the largest common divisor for the 3 numbers A, B, and C. ---> A=2x, B=3x and C=5x ---> (2x)^2+(3x)^2+(5x)^2=1368 ---> 4x^2+9x^2+25x^2=1368 ---> 38x^2=1368 ---> x^2=36 ---> x=6, A=2x=12 B)
User avatar
Mona2019
User avatar
Joined: 13 Mar 2018
Last visit: 27 Sep 2022
Posts: 190
Own Kudos:
222
 [1]
Given Kudos: 1,608
Posts: 190
Kudos: 222
 [1]
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their 22 Oct 2020, 21:41
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Let the numbers be 2x,3x,5x
Sum of their squares is
38x^2= 1368
X =6
2x=12

Posted from my mobile device
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 15 May 2026
Posts: 22,344
Own Kudos:
26,594
 [1]
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: 22,344
Kudos: 26,594
 [1]
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their 27 Oct 2020, 09:21
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their squares is 1368, what is the value of the first number?

A. 6
B. 12
C. 18
D. 24
E. 30
Show more
Solution:

We can let the three numbers be 2x, 3x, and 5x and create the equation:

(2x)^2 + (3x)^2 + (5x)^2 = 1368

4x^2 + 9x^2 + 25x^2 = 1368

38x^2 = 1368

x^2 = 36

x = 6 or x = -6

Because the answer choices are all positive, we can eliminate x = -6.

Since the first number is 2x, the first number is 2(6) = 12.

Answer: B
User avatar
Abhishek009
User avatar
Board of Directors
Joined: 11 Jun 2011
Last visit: 17 Dec 2025
Posts: 5,896
Own Kudos:
5,466
Given Kudos: 463
Status:QA & VA Forum Moderator
Location: India
GPA: 3.5
WE:Business Development (Commercial Banking)
Posts: 5,896
Kudos: 5,466
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their 27 Oct 2020, 10:21
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their squares is 1368, what is the value of the first number?

A. 6
B. 12
C. 18
D. 24
E. 30
Show more
\(2x^2 + 3x^2 + 5x^2 = 1368 \)

So, \(x^2 = 36\)

Or, \(x = 6\)

So, The first number is \(2*6 = 12\), Answer must be (B)
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 39,091
Own Kudos:
1,125
Posts: 39,091
Kudos: 1,125
If three numbers are in the ratio of 2 : 3 : 5, and the sum of their 17 Nov 2025, 21:46
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
110596 posts
Krunaal
Tuck School Moderator
852 posts