Last visit was: 23 Apr 2026, 17:51 It is currently 23 Apr 2026, 17:51
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
ezinis
Joined: 27 Oct 2009
Last visit: 04 Feb 2011
Posts: 86
Own Kudos:
456
 [10]
Given Kudos: 18
Location: Montreal
Concentration: Finance
Schools:Harvard, Yale, HEC
Posts: 86
Kudos: 456
 [10]
2
Kudos
Add Kudos
7
Bookmarks
Bookmark this Post
User avatar
bullzeye
Joined: 09 Sep 2010
Last visit: 11 Jul 2016
Posts: 41
Own Kudos:
13
 [1]
Given Kudos: 6
Location: India
Concentration: Operations, General Management
GMAT 1: 640 Q47 V34
GMAT 2: 690 Q47 V38
GPA: 3.4
WE:Information Technology (Aerospace and Defense)
GMAT 2: 690 Q47 V38
Posts: 41
Kudos: 13
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,785
Own Kudos:
Given Kudos: 105,853
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,785
Kudos: 810,870
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
EMPOWERgmatRichC
User avatar
Major Poster
Joined: 19 Dec 2014
Last visit: 31 Dec 2023
Posts: 21,777
Own Kudos:
Given Kudos: 450
Status:GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Expert
Expert reply
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Posts: 21,777
Kudos: 13,047
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi All,

This DS question is a great example of how you can TEST VALUES and keep things SIMPLE to quickly get to the solution.

We're told that A, B and C are positive integers. We're asked if (A)(B)(C) is an EVEN number. This is a YES/NO question.

Fact 1: A+B is a PRIME number

IF....
A = 1
B = 1
A+B = 1+1 = 2

IF....
C = 1, then (1)(1)(1) = 1 and the answer to the question is NO
C = 2, then (1)(1)(2) = 2 and the answer to the question is YES
Fact 1 is INSUFFICIENT

Fact 2: B+C is an EVEN number

IF....
B = 1
C = 1
B+C = 1+1 = 2

IF....
A = 1, then (1)(1)(1) = 1 and the answer to the question is NO
A = 2, then (2)(1)(1) = 2 and the answer to the question is YES
Fact 2 is INSUFFICIENT

Combined, we know...
A+B is a PRIME
B+C is EVEN

IF....
A = 1
B = 1
C = 1
Then (1)(1)(1) = 1 and the answer to the question is NO

IF...
A = 2
B = 1
C = 1
Then (2)(1)(1) = 1 and the answer to the question is YES
Combined, INSUFFICIENT

Final Answer:
GMAT assassins aren't born, they're made,
Rich
User avatar
CrackverbalGMAT
User avatar
Major Poster
Joined: 03 Oct 2013
Last visit: 22 Apr 2026
Posts: 4,846
Own Kudos:
Given Kudos: 226
Affiliations: CrackVerbal
Location: India
Expert
Expert reply
Posts: 4,846
Kudos: 9,181
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hi here ‘a or b’ anyone is not necessarily even all the time… So statement 1 is not sufficient:
Statement 1 : Not sufficient:
If a=1 , b=1 and c=3 then a+b is prime but abc is not even. Answer is NO to the question.
If a=2 , b=1 and c=3 then a+b is prime and abc is even. Answer is YES to the Question.
Statement 2 : Not sufficient:
If a=1, b=2 and c=4 then b+c(both even) is even and abc is even. Answer is YES to the question.
If a=1 , b=1 and c=3 then b+c(both odd) is even but abc is not even. Answer is NO to the Question.
So not sufficient.
So together also you can use the same example.
If a=1, b=2 and c=4 then a+b is prime and b+c(both even) is even and abc is even. Answer is YES to the question.
If a=1 , b=1 and c=3 then a+b is prime and b+c(both odd) is even but abc is not even. Answer is NO to the Question.

You can see that even together it is not sufficient.
So answer is E.
User avatar
rishabhg2712
Joined: 19 Jan 2023
Last visit: 18 Apr 2025
Posts: 34
Own Kudos:
Given Kudos: 116
Location: India
Concentration: Strategy, Leadership
GMAT 1: 660 Q48 V33
GPA: 4
GMAT 1: 660 Q48 V33
Posts: 34
Kudos: 9
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
ezinis
Lets see if anybody falls into the trap here:

If a, b and c are all positive integers, is abc an even number?
(1) a+b is a prime number
(2) b+c is an even number

For \(abc\) to be an even number at least one of the multiples must be even (since a, b and c are all positive integers), so the question basically asks whether either of unknown is even.

(1) a+b is a prime number --> if \(a+b=odd \ prime\), for example 3, then either \(a\) or \(b\) must be even and the answer to the question will be YES (the sum of two integers to be odd one must be odd and the other even) BUT if \(a+b=2=prime\) then \(a=b=1\) and in case \(c=odd\) the answer to the question will be NO. Not sufficient.

(2) b+c is an even number --> either both are even or both are odd. Not sufficient.

(1)+(2) Still not sufficient: if \(a=1\) and \(b=c=2\) (\(a+b=3=prime\) and \(b+c=4=even\)) then the answer will be YES but if \(a=b=c=1\)(\(a+b=2=prime\) and \(b+c=2=even\)) then the answer will be NO. Not sufficient.

Answer: E.

Hi Bunuel,

Is it ALWAYS explicitly stated (in GMAT) when variables considered in question are different numbers?

For example, in this question, I am confused whether given variables denote different number or can have same number, since a b & c are different variables. This confusion led me to the wrong answer as I did not consider the case where a can be equal to b.

Regards,
Rishabh
User avatar
EMPOWERgmatRichC
User avatar
Major Poster
Joined: 19 Dec 2014
Last visit: 31 Dec 2023
Posts: 21,777
Own Kudos:
Given Kudos: 450
Status:GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Expert
Expert reply
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Posts: 21,777
Kudos: 13,047
Kudos
Add Kudos
Bookmarks
Bookmark this Post
rishabhg2712
Bunuel
ezinis
Lets see if anybody falls into the trap here:

If a, b and c are all positive integers, is abc an even number?
(1) a+b is a prime number
(2) b+c is an even number

For \(abc\) to be an even number at least one of the multiples must be even (since a, b and c are all positive integers), so the question basically asks whether either of unknown is even.

(1) a+b is a prime number --> if \(a+b=odd \ prime\), for example 3, then either \(a\) or \(b\) must be even and the answer to the question will be YES (the sum of two integers to be odd one must be odd and the other even) BUT if \(a+b=2=prime\) then \(a=b=1\) and in case \(c=odd\) the answer to the question will be NO. Not sufficient.

(2) b+c is an even number --> either both are even or both are odd. Not sufficient.

(1)+(2) Still not sufficient: if \(a=1\) and \(b=c=2\) (\(a+b=3=prime\) and \(b+c=4=even\)) then the answer will be YES but if \(a=b=c=1\)(\(a+b=2=prime\) and \(b+c=2=even\)) then the answer will be NO. Not sufficient.

Answer: E.

Hi Bunuel,

Is it ALWAYS explicitly stated (in GMAT) when variables considered in question are different numbers?

For example, in this question, I am confused whether given variables denote different number or can have same number, since a b & c are different variables. This confusion led me to the wrong answer as I did not consider the case where a can be equal to b.

Regards,
Rishabh

Hi Rishabh,

The answer to your immediate question is NO: if you are dealing with multiple variables, unless the prompt explicitly states that the variables are differenent numbers, then you should NOT assume that they have to be different.

GMAT assassins aren't born, they're made,
Rich

Contact Rich at: [email protected]
www.empowergmat.com
Moderators:
Math Expert
109785 posts
498 posts
212 posts