Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 25 May 2017, 17:10

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

Is product 2*x*5*y an even integer? 1. 2 + x + 5 + y is an

Author Message
VP
Joined: 22 Nov 2007
Posts: 1082
Followers: 8

Kudos [?]: 566 [0], given: 0

Is product 2*x*5*y an even integer? 1. 2 + x + 5 + y is an [#permalink]

Show Tags

02 Mar 2008, 04:22
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
Director
Joined: 10 Sep 2007
Posts: 943
Followers: 8

Kudos [?]: 302 [0], given: 0

Show Tags

02 Mar 2008, 07:45
Question can be restated as is 5XY (as 2 is already an even number) is even integer or not?

Statment 1:
Implies x + 5 + y => (X+Y) is odd as ODD +ODD = Even (5 is Odd so X+Y has to be Odd)
X+Y can be odd in many ways, even for fractions it will hold true.
So this statement alone cannot answer the question.

Statement 2:
x - y is an odd integer again this can be odd in many ways, even for fractions it will hold true.
So this statement alone cannot answer the question.

Now combine both statements
X+Y = ODD integer and X-Y= Odd integer, again this can be fulfilled by infinite possibilities including fraction.
E.g. X=4.5, Y=3.5 or X=5, Y=4
So this question cannot be answered with these statements.

SVP
Joined: 28 Dec 2005
Posts: 1561
Followers: 3

Kudos [?]: 158 [0], given: 2

Show Tags

02 Mar 2008, 07:56
i get D.

from stat 1, we are told that 7+x+y=even. that means either x is even and y is odd, or vice versa. they cant both be even or both be odd.

now, regardless of which is even and which is odd, 2x5y will always be even. (2x) will always be even, because you either have even x even = even, or even x odd = even. For 5y, you have either odd x even, or odd x odd, which gives odd or even, but when multiplied by the even result from 2x, you always get an even number.

from stat 2, x-y=odd. again, x can be odd/even, and so can y. same situation as above. suff.
VP
Joined: 22 Nov 2007
Posts: 1082
Followers: 8

Kudos [?]: 566 [0], given: 0

Show Tags

02 Mar 2008, 10:10
abhijit_sen wrote:
Question can be restated as is 5XY (as 2 is already an even number) is even integer or not?

Statment 1:
Implies x + 5 + y => (X+Y) is odd as ODD +ODD = Even (5 is Odd so X+Y has to be Odd)
X+Y can be odd in many ways, even for fractions it will hold true.
So this statement alone cannot answer the question.

Statement 2:
x - y is an odd integer again this can be odd in many ways, even for fractions it will hold true.
So this statement alone cannot answer the question.

Now combine both statements
X+Y = ODD integer and X-Y= Odd integer, again this can be fulfilled by infinite possibilities including fraction.
E.g. X=4.5, Y=3.5 or X=5, Y=4
So this question cannot be answered with these statements.

actually if you build a system you'll have:

x+y=odd
x-y=odd

2x=even, thus x would be an integer, never mind if odd/even. if x is an integer y is an integer as well from our system. thus 10xy would be even for sure. OA is C
Manager
Joined: 15 Nov 2007
Posts: 135
Followers: 1

Kudos [?]: 54 [0], given: 2

Show Tags

02 Mar 2008, 13:40
marcodonzelli wrote:
abhijit_sen wrote:
Question can be restated as is 5XY (as 2 is already an even number) is even integer or not?

Statment 1:
Implies x + 5 + y => (X+Y) is odd as ODD +ODD = Even (5 is Odd so X+Y has to be Odd)
X+Y can be odd in many ways, even for fractions it will hold true.
So this statement alone cannot answer the question.

Statement 2:
x - y is an odd integer again this can be odd in many ways, even for fractions it will hold true.
So this statement alone cannot answer the question.

Now combine both statements
X+Y = ODD integer and X-Y= Odd integer, again this can be fulfilled by infinite possibilities including fraction.
E.g. X=4.5, Y=3.5 or X=5, Y=4
So this question cannot be answered with these statements.

actually if you build a system you'll have:

x+y=odd
x-y=odd

2x=even, thus x would be an integer, never mind if odd/even. if x is an integer y is an integer as well from our system. thus 10xy would be even for sure. OA is C

sorry, dumb question but isn't it even by default? (2*?)
VP
Joined: 22 Nov 2007
Posts: 1082
Followers: 8

Kudos [?]: 566 [0], given: 0

Show Tags

02 Mar 2008, 22:43
[/quote]

sorry, dumb question but isn't it even by default? (2*?)[/quote]

you don't know whether x and y are integers
Re: Odd/even integers   [#permalink] 02 Mar 2008, 22:43
Display posts from previous: Sort by