It is currently 21 Oct 2017, 18:02

### 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

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

# odds and evens

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Current Student
Joined: 11 May 2008
Posts: 555

Kudos [?]: 222 [0], given: 0

odds and evens [#permalink]

### Show Tags

28 Aug 2008, 20:28
1
This post was
BOOKMARKED
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 100% (00:55) wrong based on 5 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Is product 2*x*5*y an even integer?

1. 2 + x + 5 + y is an even integer
2. x - y is an odd integer

Kudos [?]: 222 [0], given: 0

SVP
Joined: 07 Nov 2007
Posts: 1792

Kudos [?]: 1063 [0], given: 5

Location: New York
Re: odds and evens [#permalink]

### Show Tags

28 Aug 2008, 21:03
arjtryarjtry wrote:
Is product 2*x*5*y an even integer?

1. 2 + x + 5 + y is an even integer
2. x - y is an odd integer

1)
x and y can be integers or fractions..
x=3.5 y=1.5 is not even integer
x=3 y=2 sum is even integer

insufficient

2) x - y
x and y can be integers or fractions..

combine
x+y= odd

x-y = odd

2x= odd+odd= even
2y= odd-odd= even

2*x*5*y = even*5* even/2 = integer.

So..
C.
_________________

Smiling wins more friends than frowning

Last edited by x2suresh on 29 Aug 2008, 21:29, edited 1 time in total.

Kudos [?]: 1063 [0], given: 5

Director
Joined: 14 Aug 2007
Posts: 726

Kudos [?]: 212 [0], given: 0

Re: odds and evens [#permalink]

### Show Tags

28 Aug 2008, 21:18
arjtryarjtry wrote:
Is product 2*x*5*y an even integer?

1. 2 + x + 5 + y is an even integer
2. x - y is an odd integer

E for me.

1) as 2 is even 1) implies that , x+y+5 = even, which implies that
x+y is odd.
3.5 + 3.5 => not even integer.
2 + 3 => even integer.

Insuff

2) 4.5 - 3.5 = 1 => not an even integer
4 + 5 => even integer

Insuff.

Combined:
again, x & y can be fractions or can be integers
so insuff

E

Kudos [?]: 212 [0], given: 0

SVP
Joined: 17 Jun 2008
Posts: 1534

Kudos [?]: 279 [0], given: 0

Re: odds and evens [#permalink]

### Show Tags

28 Aug 2008, 23:15
I will go with C.

If x + y is an odd integer and x - y is also an odd integere then both x and y must be integers. If x and / or y are fractions, the above conditions will not satisfy.

Kudos [?]: 279 [0], given: 0

Current Student
Joined: 11 May 2008
Posts: 555

Kudos [?]: 222 [0], given: 0

Re: odds and evens [#permalink]

### Show Tags

28 Aug 2008, 23:21
ans iS C. good expln suresh!!!+1

Kudos [?]: 222 [0], given: 0

Manager
Joined: 28 Jul 2004
Posts: 136

Kudos [?]: 73 [0], given: 2

Location: Melbourne
Schools: Yale SOM, Tuck, Ross, IESE, HEC, Johnson, Booth
Re: odds and evens [#permalink]

### Show Tags

29 Aug 2008, 20:47
answer by Suresh is correct but explanation is wrong.

if x + y = odd and x - y = odd implies that

2x = odd + odd = even = 2 * integer -> x is an integer

similarly 2y = odd - odd = even inetger = 2 * integer -> y is an integer

hence 2*x*5*y is an integer and (C) is the answer !!
_________________

kris

Kudos [?]: 73 [0], given: 2

SVP
Joined: 07 Nov 2007
Posts: 1792

Kudos [?]: 1063 [0], given: 5

Location: New York
Re: odds and evens [#permalink]

### Show Tags

29 Aug 2008, 21:29
krishan wrote:
answer by Suresh is correct but explanation is wrong.

if x + y = odd and x - y = odd implies that

2x = odd + odd = even = 2 * integer -> x is an integer

similarly 2y = odd - odd = even inetger = 2 * integer -> y is an integer

hence 2*x*5*y is an integer and (C) is the answer !!

Agreed. Thanks for pointing out.

I modified that.
_________________

Smiling wins more friends than frowning

Kudos [?]: 1063 [0], given: 5

Re: odds and evens   [#permalink] 29 Aug 2008, 21:29
Display posts from previous: Sort by

# odds and evens

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.