• Veritas Prep
    Free Veritas GMAT Class
    Experience Lesson 1 Live Free

    Available with Beat the GMAT members only code

    MORE DETAILS
    Veritas Prep
  • Varsity Tutors
    Award-winning private GMAT tutoring
    Register now and save up to $200

    Available with Beat the GMAT members only code

    MORE DETAILS
    Varsity Tutors
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh
  • Economist Test Prep
    Free Trial & Practice Exam
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • EMPOWERgmat Slider
    1 Hour Free
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • Target Test Prep
    5-Day Free Trial
    5-day free, full-access trial TTP Quant

    Available with Beat the GMAT members only code

    MORE DETAILS
    Target Test Prep
  • e-gmat Exclusive Offer
    Get 300+ Practice Questions
    25 Video lessons and 6 Webinars for FREE

    Available with Beat the GMAT members only code

    MORE DETAILS
    e-gmat Exclusive Offer
  • Kaplan Test Prep
    Free Practice Test & Review
    How would you score if you took the GMAT

    Available with Beat the GMAT members only code

    MORE DETAILS
    Kaplan Test Prep
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT

OG12 #106: if x and y are integers, is xy even?

This topic has 2 expert replies and 5 member replies
Fractal Master | Next Rank: 500 Posts Default Avatar
Joined
22 Aug 2010
Posted:
183 messages
Upvotes:
5
Test Date:
24.09.2011
Target GMAT Score:
700

OG12 #106: if x and y are integers, is xy even?

Post Wed Sep 15, 2010 6:46 am
if x and y are integers, is xy even?

(1) x = y + 1
(2) x/y is an even integer

according to og, the solution is: D

Why is (1) sufficient? I mean, x could be 1 and y could be 0 --> xy would not be even, because xy = 0! but x could also be 2 and y=1, then xy=2 which is even! so for me, (1) is insufficient!

?

thx for hlp

  • +1 Upvote Post
  • Quote
  • Flag
Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!
Top Reply
Post Sat Dec 29, 2012 6:58 am
Fractal wrote:
if x and y are integers, is xy even?

(1) x = y + 1
(2) x/y is an even integer

When posting questions, please use the spoiler function to hide the correct answer. This will allow others to attempt the question without seeing the final answer.

Target question: Is xy even?

Aside: For xy to be even, we need x to be even, or y to be even (or both even).

Statement 1: x = y+1
This tells us that x is 1 greater than y.
This means that x and y are consecutive integers.
If x and y are consecutive integers, then one must be odd and the other must be even.
As such, the product xy must be even.
So, statement 1 is SUFFICIENT

Statement 2: x/y is an even integer.
If x/y is an even integer, then we can write x/y = 2k (where k is an integer)
Now take the equation and multiply both sides by y to get: x = 2ky
If k and y are both integers, we can see that 2ky (also known as x) must be even.
If x is even, then the product xy must be even.
So, statement 2 is SUFFICIENT

Answer = D

Cheers,
Brent

_________________
Brent Hanneson – Founder of GMATPrepNow.com
Use our video course along with Beat The GMAT's free 60-Day Study Guide

Check out the online reviews of our course
Come see all of our free resources

  • +1 Upvote Post
  • Quote
  • Flag
GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!
kaiweiweiwei Junior | Next Rank: 30 Posts
Joined
07 Aug 2012
Posted:
14 messages
Top Reply
Post Sun Dec 30, 2012 5:54 pm
If y=0 and x=1, is xy still even?

I forget if 0 is even or not.

  • +1 Upvote Post
  • Quote
  • Flag
Post Sat Dec 29, 2012 6:58 am
Fractal wrote:
if x and y are integers, is xy even?

(1) x = y + 1
(2) x/y is an even integer

When posting questions, please use the spoiler function to hide the correct answer. This will allow others to attempt the question without seeing the final answer.

Target question: Is xy even?

Aside: For xy to be even, we need x to be even, or y to be even (or both even).

Statement 1: x = y+1
This tells us that x is 1 greater than y.
This means that x and y are consecutive integers.
If x and y are consecutive integers, then one must be odd and the other must be even.
As such, the product xy must be even.
So, statement 1 is SUFFICIENT

Statement 2: x/y is an even integer.
If x/y is an even integer, then we can write x/y = 2k (where k is an integer)
Now take the equation and multiply both sides by y to get: x = 2ky
If k and y are both integers, we can see that 2ky (also known as x) must be even.
If x is even, then the product xy must be even.
So, statement 2 is SUFFICIENT

Answer = D

Cheers,
Brent

_________________
Brent Hanneson – Founder of GMATPrepNow.com
Use our video course along with Beat The GMAT's free 60-Day Study Guide

Check out the online reviews of our course
Come see all of our free resources

  • +1 Upvote Post
  • Quote
  • Flag
GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!
kaiweiweiwei Junior | Next Rank: 30 Posts
Joined
07 Aug 2012
Posted:
14 messages
Post Sun Dec 30, 2012 5:54 pm
If y=0 and x=1, is xy still even?

I forget if 0 is even or not.

  • +1 Upvote Post
  • Quote
  • Flag
Post Sun Dec 30, 2012 5:58 pm
0 is, indeed, even.

Cheers,
Brent

_________________
Brent Hanneson – Founder of GMATPrepNow.com
Use our video course along with Beat The GMAT's free 60-Day Study Guide

Check out the online reviews of our course
Come see all of our free resources

  • +1 Upvote Post
  • Quote
  • Flag
GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!
buzzdeepak Senior | Next Rank: 100 Posts Default Avatar
Joined
17 Sep 2012
Posted:
56 messages
Followed by:
1 members
Upvotes:
13
GMAT Score:
710
Post Sat Dec 29, 2012 4:06 am
What if x=2 and y=4?

OG solution says they are consecutive but the question doesn't state that....

IMO Ans= B.

  • +1 Upvote Post
  • Quote
  • Flag
Fractal Master | Next Rank: 500 Posts Default Avatar
Joined
22 Aug 2010
Posted:
183 messages
Upvotes:
5
Test Date:
24.09.2011
Target GMAT Score:
700
Post Wed Sep 15, 2010 7:53 am
thx a lot

and i am sorry for that question. i should have known it! i just looked it up in kaplan; 0 is even!

  • +1 Upvote Post
  • Quote
  • Flag

Best Conversation Starters

1 lheiannie07 120 topics
2 ardz24 65 topics
3 LUANDATO 63 topics
4 swerve 61 topics
5 AAPL 59 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 image description Scott@TargetTestPrep

Target Test Prep

186 posts
2 image description Brent@GMATPrepNow

GMAT Prep Now Teacher

171 posts
3 image description Jeff@TargetTestPrep

Target Test Prep

147 posts
4 image description Rich.C@EMPOWERgma...

EMPOWERgmat

133 posts
5 image description GMATGuruNY

The Princeton Review Teacher

128 posts
See More Top Beat The GMAT Experts