Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 23 Jul 2016, 13:01

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If x and y are positive integers, is x^2*y^2 even ? (1) x +

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

### Hide Tags

Senior Manager
Status: Do and Die!!
Joined: 15 Sep 2010
Posts: 326
Followers: 1

Kudos [?]: 338 [1] , given: 193

If x and y are positive integers, is x^2*y^2 even ? (1) x + [#permalink]

### Show Tags

19 Oct 2010, 10:23
1
This post received
KUDOS
1
This post was
BOOKMARKED
00:00

Difficulty:

55% (hard)

Question Stats:

52% (02:10) correct 48% (00:58) wrong based on 64 sessions

### HideShow timer Statistics

If x and y are positive integers, is x^2*y^2 even ?

(1) x + 5 is a prime number

(2) y + 1 is a prime number
[Reveal] Spoiler: OA

_________________

I'm the Dumbest of All !!

Last edited by Bunuel on 20 Oct 2010, 13:47, edited 1 time in total.
Edited the stem.
Intern
Joined: 29 Sep 2010
Posts: 13
Schools: IMD '16 (A)
GMAT 1: 730 Q47 V44
Followers: 0

Kudos [?]: 6 [0], given: 1

Re: Number properties [#permalink]

### Show Tags

19 Oct 2010, 10:36
A for me.

First off, an even number squared will give an even number(2^2 = 4, 4^2 = 16 etc). An odd number squared will give an odd number (3^2 = 9, 5^2 = 25 etc). Also, for the multiplication between two numbers to come out even, at least one of the numbers must be even.

We know all primes except for 2 are odd. Since x and y are positive, the only way for x + 5 to be prime will be if x is even (i.e. if x = 1 then x + 5 = 6 which is not prime. But if x = 2 then x + 5 = 7 which is prime). Therefore, x^2 will also be even and x^2y^2 will also be even regardless of what y is. statement 1 is sufficient.

Using a similar approach for condition 2, we can set y = 1 (y + 1 = 2 which is prime) or y = 2 (y + 2 = 3 which is also prime). So we see with this condition, y can be both even or odd. So statement 2 alone is not sufficient.
Math Expert
Joined: 02 Sep 2009
Posts: 33996
Followers: 6074

Kudos [?]: 76238 [1] , given: 9969

Re: Number properties [#permalink]

### Show Tags

19 Oct 2010, 10:37
1
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
shrive555 wrote:
If x and y are positive integers, is x2y2 even ?

(1) x + 5 is a prime number

(2) y + 1 is a prime number

In order $$x^2y^2$$ to be even at least one of the unknowns must be even.

(1) $$x+5=prime$$ --> as $$x$$ is a positive integer then this prime can not be the only even prime 2 (in this case $$x+5=2$$ --> $$x=-3=negative$$), so $$x+5=prime=odd$$ --> $$x=odd-5=odd-odd=even$$. Sufficient.

(2) y + 1 is a prime number --> $$y$$ could be 1, so odd, and we won't be sure whether $$x^2y^2=even$$ or $$y$$ could be even (for example 2) and then $$x^2y^2=even$$. Not sufficient.

Answer: A.
_________________
Current Student
Joined: 15 Jul 2010
Posts: 256
GMAT 1: 750 Q49 V42
Followers: 8

Kudos [?]: 153 [0], given: 65

Re: Number properties [#permalink]

### Show Tags

20 Oct 2010, 13:45
A.

Kind of trivial but I was staring at x2y2 for 20 seconds.

edit it to x^2y^2 for others maybe?
_________________

Consider KUDOS if my post was helpful.

My Debrief: http://gmatclub.com/forum/750-q49v42-105591.html#p825487

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 10561
Followers: 495

Kudos [?]: 129 [0], given: 0

Re: If x and y are positive integers, is x^2*y^2 even ? (1) x + [#permalink]

### Show Tags

12 Apr 2015, 21:20
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 10561
Followers: 495

Kudos [?]: 129 [0], given: 0

Re: If x and y are positive integers, is x^2*y^2 even ? (1) x + [#permalink]

### Show Tags

08 Jun 2016, 04:53
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: If x and y are positive integers, is x^2*y^2 even ? (1) x +   [#permalink] 08 Jun 2016, 04:53
Similar topics Replies Last post
Similar
Topics:
11 Is x^2 - y^2 an even integer? 8 05 Jun 2016, 01:07
1 If x and y are positive integers, is x^2 – y^2 an even integer? 6 18 Apr 2016, 01:20
11 If x is a positive integer, is (x^2 + y^2)^1/2 an integer? 6 24 Mar 2015, 04:30
3 If x and y are positive integers such that x^2+y^2 is a prim 3 27 Feb 2013, 14:19
1 Is x^2 - y^2 divisible by 8? 1. x and y are even integers. 16 07 Dec 2009, 03:15
Display posts from previous: Sort by

# If x and y are positive integers, is x^2*y^2 even ? (1) x +

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

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.