Last visit was: 21 Apr 2026, 14:25 It is currently 21 Apr 2026, 14:25
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: 21 Apr 2026
Posts: 109,728
Own Kudos:
810,463
 [12]
Given Kudos: 105,800
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: 109,728
Kudos: 810,463
 [12]
If a, b and c are integers, is (a·b) a multiple of 18? 12 Mar 2021, 01:15
Kudos
Add Kudos
12
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:

65% (hard)

Question Stats:

55% (01:59) correct 45% (01:56) wrong based on 142 sessions

History

Date
Time
Result
Not Attempted Yet
If a, b and c are integers, is (a·b) a multiple of 18?

(1) 2a = 3b
(2) 2b = 3c
 
ShowHide Answer
Official Answer
C
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 21 Apr 2026
Posts: 109,728
Own Kudos:
810,463
 [1]
Given Kudos: 105,800
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: 109,728
Kudos: 810,463
 [1]
If a, b and c are integers, is (a·b) a multiple of 18? 15 Mar 2021, 00:30
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Bunuel
If a, b and c are integers, is (a·b) a multiple of 18?

(1) 2a = 3b
(2) 2b = 3c
Show more
If a, b and c are integers, is (a·b) a multiple of 18?

Notice that we are told that all variables are integers.

(1) 2a = 3b --> a/b = 3/2. a is a multiple of 3 and b is a multiple of 2. ab must be a multiple of 6 but may or may not be a multiple of 18 (for example consider (a,b) = (3,2) and (a,b) = 9,6). Not sufficient.

(2) 2b = 3c --> b/c = 3/2. b is a multiple of 3. Not sufficient.

(1)+(2) b is a multiple of both 2 and 3, so it must be a multiple of 6 and since a is a multiple of 3, then ab must be a multiple of 6*3 = 18. Sufficient.

Answer: C.

Hope it's clear.­
General Discussion
avatar
Kyala1Jameson
avatar
Joined: 09 Mar 2021
Last visit: 11 Jul 2021
Posts: 28
Own Kudos:
30
 [1]
Given Kudos: 25
Location: South Africa
Concentration: Leadership, Marketing
Schools: LBS MAM "23
GPA: 3.01
WE:Design (Computer Software)
Schools: LBS MAM "23
Posts: 28
Kudos: 30
 [1]
If a, b and c are integers, is (a·b) a multiple of 18? 12 Mar 2021, 07:54
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
imo C
If a, b and c are integers, is (a·b) a multiple of 18?

(1) 2a = 3b
b= 2a/3
if a = 3 , b = 2 => ab = 6
if a= 18 , b= 12 => ab = 18 (12) .. Multiple of 18 ...
Not sufficient

(2) 2b = 3c
No info about a so
not sufficient ..

no combining 1 and 2 ..

b= 2a/3
c = 2b/3
since minimum of b has to be 6 (in form of 6n , n 1,2,3 ...) to satisfy a b c are integer ..
if b = 6 , c = 4 , a = 9 ... ab = 18 (something) .. multiple of 18 ...
.. Sufficient
avatar
TarunKumar1234
avatar
Joined: 14 Jul 2020
Last visit: 28 Feb 2024
Posts: 1,103
Own Kudos:
1,357
 [2]
Given Kudos: 351
Location: India
Posts: 1,103
Kudos: 1,357
 [2]
If a, b and c are integers, is (a·b) a multiple of 18? 12 Mar 2021, 21:54
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
If a, b and c are integers, is (a·b) a multiple of 18?

Stat 1: 2a = 3b
It means, a = multiple of 3 and b= multiple of 2. Now, (a·b) can be multiple of 6, which means either multiple of 18 or not. Not sufficient

Stat 2: 2b = 3c
It means, b = multiple of 3 and c= multiple of 2. But we don't know anything about a. Not sufficient

Combining both, a = multiple of 3 and b= multiple of 2 & 3. Now, (a·b) can be multiple of 18. Sufficient

So, I think C. :)
avatar
GCMEMBER
avatar
Joined: 09 Dec 2019
Last visit: 03 Jun 2021
Posts: 123
Own Kudos:
176
 [2]
Given Kudos: 5
Posts: 123
Kudos: 176
 [2]
If a, b and c are integers, is (a·b) a multiple of 18? 14 Mar 2021, 00:44
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
If a, b and c are integers, is (a·b) a multiple of 18?

(1) 2a = 3b
a = 3b/2

Put b = 2, a = 3 and a.b = 6, which is not a multiple of 18

Put b = 6, a = 9 and a.b = 54, multiple of 18
Not sufficient

(2) 2b = 3c
b = 3c/2

Put c = 2, then b = 3 and put a = 1, a.b = 3

Put c = 2, then b = 3 and put a = 6, a.b = 18

Not sufficient

(1) + (2)

2b = 3c
b = 3c/2

2a = 3b
2a = 3(3c/2)
a = 9c/4

Since a, b, and C are integers. Minimum value of c = 4

For c = 4, a = 9, b = 6

a.b = 54

So, For any value of c, a is always a multiple of 9 and b is always a multiple if 6. Thus, a.b is always a multiple of 18

Sufficient

Option C

Posted from my mobile device
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,955
Own Kudos:
1,117
Posts: 38,955
Kudos: 1,117
If a, b and c are integers, is (a·b) a multiple of 18? 01 Jul 2024, 20:15
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
109728 posts
kingbucky
498 posts
Gmat860sanskar
211 posts