GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 21 Apr 2019, 02:03

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 x is an integer, is y an integer?

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

Hide Tags

 
Manager
Manager
avatar
Joined: 10 Feb 2011
Posts: 107
If x is an integer, is y an integer?  [#permalink]

Show Tags

New post Updated on: 03 Sep 2017, 06:44
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

63% (01:34) correct 37% (01:37) wrong based on 65 sessions

HideShow timer Statistics

If x is an integer, is y an integer?

(1) The average (arithmetic mean) of x and y is an integer.
(2) The average (arithmetic mean) of x, y, and y + 4 is x.

Originally posted by banksy on 15 Mar 2011, 16:46.
Last edited by Bunuel on 03 Sep 2017, 06:44, edited 1 time in total.
Edited the OA.
Manager
Manager
avatar
Joined: 05 Jan 2011
Posts: 121
Re: If x is an integer, is y an integer?  [#permalink]

Show Tags

New post 15 Mar 2011, 19:16
banksy wrote:
8. (MH) If x is an integer, is y an integer?
(1) The average (arithmetic mean) of x and y is an integer.
(2) The average (arithmetic mean) of x, y, and y + 4 is x.



1. (x + y)/2 is an integer
i.e x + y => integer
Therefore Y is an integer since x is an integer and X+Y is also an integer
eg . x+y=5 IF x=3 then y will be 2 (both integer)
Similarly if x=2.5 y will be 2.5 (both non integer) sufficient

2. x+y+y+4=3x
x-y=4
x is an integer (x-y) is an integer .... therefore y must also be an integer sufficient
Retired Moderator
avatar
B
Joined: 16 Nov 2010
Posts: 1393
Location: United States (IN)
Concentration: Strategy, Technology
Reviews Badge
Re: If x is an integer, is y an integer?  [#permalink]

Show Tags

New post 15 Mar 2011, 19:36
1
I think the OA is wrong, it should be D.

From (1), (x+y)/2 = k, where k is an integer, so y = 2k - x, an integer - integer = integer, so (1) is sufficient.

From (2) (x + y + y + 4)/3 = x => x + 2y + 4 = 3x => 2x-2y = 4 => x-y = 2, so y = x + 2, an integer + integer = integer, so (2) is sufficient.

Hence the answer is D.
_________________
Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)

GMAT Club Premium Membership - big benefits and savings
Manager
Manager
avatar
Joined: 05 Jan 2011
Posts: 121
Re: If x is an integer, is y an integer?  [#permalink]

Show Tags

New post 15 Mar 2011, 20:34
banksy wrote:
8. (MH) If x is an integer, is y an integer?
(1) The average (arithmetic mean) of x and y is an integer.
(2) The average (arithmetic mean) of x, y, and y + 4 is x.



hey,
Please share with us the souce.... OA seems to be wrong
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 54376
Re: If x is an integer, is y an integer?  [#permalink]

Show Tags

New post 03 Sep 2017, 06:43
banksy wrote:
If x is an integer, is y an integer?

(1) The average (arithmetic mean) of x and y is an integer.
(2) The average (arithmetic mean) of x, y, and y + 4 is x.


If x is an integer, is y an integer?

(1) The average (arithmetic mean) of x and y is an integer --> \(\frac{x + y}{2}=integer\) --> \(x+y=2*integer=integer\) --> \(y = integer-x=integer-integer=integer\). Sufficient.

(2) The average (arithmetic mean) of x, y, and y + 4 is x --> \(\frac{x + y+y+4}{3}=x\) --> \(y=x-2=integer-integer=integer\). Sufficient.

Answer: D.

Edited the OA, it's D not C.

Similar question to practice from OG: https://gmatclub.com/forum/if-x-is-an-i ... 68098.html
_________________
GMAT Club Bot
Re: If x is an integer, is y an integer?   [#permalink] 03 Sep 2017, 06:43
Display posts from previous: Sort by

If x is an integer, is y an integer?

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

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

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®.