Summer is Coming! Join the Game of Timers Competition to Win Epic Prizes. Registration is Open. Game starts Mon July 1st.

It is currently 19 Jul 2019, 16:31

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

If r and s are both positive integers, is the product of r and s even?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 56300
If r and s are both positive integers, is the product of r and s even?  [#permalink]

Show Tags

New post 21 Aug 2018, 13:22
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

70% (00:55) correct 30% (00:49) wrong based on 37 sessions

HideShow timer Statistics


Intern
Intern
avatar
B
Joined: 03 Sep 2017
Posts: 10
Location: India
GMAT 1: 720 Q47 V42
GPA: 3.4
Re: If r and s are both positive integers, is the product of r and s even?  [#permalink]

Show Tags

New post 21 Aug 2018, 13:31
S1: out of two consecutive integers, one will always be even, hence their product will be even. Sufficient

S2: any prime number greater than 3 is odd and hence will be followed by an even number. Hence s-1 is odd and s is even. Hence, the product of r and s will be even. Sufficient.

I vote that the answer is d

Posted from my mobile device
Director
Director
User avatar
G
Joined: 20 Feb 2015
Posts: 790
Concentration: Strategy, General Management
Premium Member
If r and s are both positive integers, is the product of r and s even?  [#permalink]

Show Tags

New post Updated on: 21 Aug 2018, 13:41
Bunuel wrote:
If r and s are both positive integers, is the product of r and s even?

(1) r and s are consecutive integers.

(2) (s - 1) is a prime number greater than 3.


(1) r and s are consecutive integers.
This case will always result in an even number
sufficient.

(2) (s - 1) is a prime number greater than 3.
say
s=6
as even * odd/even=even

D

corrected thanks !!

Originally posted by CounterSniper on 21 Aug 2018, 13:35.
Last edited by CounterSniper on 21 Aug 2018, 13:41, edited 1 time in total.
Intern
Intern
avatar
B
Joined: 03 Sep 2017
Posts: 10
Location: India
GMAT 1: 720 Q47 V42
GPA: 3.4
Re: If r and s are both positive integers, is the product of r and s even?  [#permalink]

Show Tags

New post 21 Aug 2018, 13:38
1
CounterSniper wrote:
Bunuel wrote:
If r and s are both positive integers, is the product of r and s even?

(1) r and s are consecutive integers.

(2) (s - 1) is a prime number greater than 3.


(1) r and s are consecutive integers.
This case will always result in an even number
sufficient.

(2) (s - 1) is a prime number greater than 3.
say
s=6
r=?
insufficient .

A


I don't think the value of r should matter if it's proved that s is even, since any number multiplied by an even number is even

Posted from my mobile device
VP
VP
User avatar
D
Joined: 31 Oct 2013
Posts: 1392
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
If r and s are both positive integers, is the product of r and s even?  [#permalink]

Show Tags

New post 21 Aug 2018, 13:56
Bunuel wrote:
If r and s are both positive integers, is the product of r and s even?

(1) r and s are consecutive integers.

(2) (s - 1) is a prime number greater than 3.



we are looking for the the product of rs, whether it's even or not.

Statement 1: r ans s are consecutive integers. r= 2 s = 3. rs = 6. Sufficient.

Statement 2: s - 1 = prime. Note: only even prime is 2. So, s has to be an even number for sure. even * odd / even = even .


The best answer is D.
Director
Director
User avatar
V
Joined: 06 Jan 2015
Posts: 681
Location: India
Concentration: Operations, Finance
GPA: 3.35
WE: Information Technology (Computer Software)
Premium Member
Re: If r and s are both positive integers, is the product of r and s even?  [#permalink]

Show Tags

New post 21 Aug 2018, 19:52
Bunuel wrote:
If r and s are both positive integers, is the product of r and s even?

(1) r and s are consecutive integers.

(2) (s - 1) is a prime number greater than 3.


r*s =?

(1) r and s are consecutive integers.

For any consecutive integers one has to be even and odd

Hence even*odd=even

Suff

(2) (s - 1) is a prime number greater than 3

If (s-1) is prime number s has to be even

Hence Suff

Hence D
_________________
आत्मनॊ मोक्षार्थम् जगद्धिताय च

Resource: GMATPrep RCs With Solution
GMAT Club Bot
Re: If r and s are both positive integers, is the product of r and s even?   [#permalink] 21 Aug 2018, 19:52
Display posts from previous: Sort by

If r and s are both positive integers, is the product of r and s even?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne