|
Author |
Message |
|
TAGS:
|
|
|
Manager
Joined: 11 Feb 2011
Posts: 152
Followers: 3
Kudos [?]:
6
[0], given: 21
|
y and z are nin zero integers ,is the square of (y+z) even? [#permalink]
 04 May 2011, 18:20
Question Stats:
80% (01:20) correct
20% (01:10) wrong based on 1 sessions
y and z are nin zero integers ,is the square of (y+z) even? 1.y-z is odd 2.yz is even
_________________
target:-810 out of 800!
|
|
|
|
|
|
|
Director
Joined: 03 Feb 2011
Posts: 944
Followers: 9
Kudos [?]:
137
[0], given: 121
|
Re: odds and evens! [#permalink]
04 May 2011, 18:56
The question can rephrased as - Is y even and z odd or vice versa? or Are both even or both odd? Answering any of these questions will answer our question. 1) Sufficient y may be even or z odd and vice versa. The answer is always NO PS : It is given that y and z are NON ZERO. 2) Insufficient Both may be even or just one of them may be even. In the first case y + z = even. The answer is YES In the second case y + z = odd. The answer is NO Answer A AnkitK wrote: y and z are nin zero integers ,is the square of (y+z) even?
1.y-z is odd
2.yz is even
|
|
|
|
|
|
SVP
Joined: 16 Nov 2010
Posts: 1721
Location: United States (IN)
Concentration: Strategy, Technology
Followers: 26
Kudos [?]:
227
[0], given: 34
|
Re: odds and evens! [#permalink]
04 May 2011, 19:04
(1) One of y or z is even, and one of y or z is odd So y+z is odd hence (y+z)^2 = odd Sufficient (2) y can be even, z can be odd y can be odd, z can be even y or z can both be even So square of (y+z) is even. Not Sufficient Answer - A
_________________
Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)
Find out what's new at GMAT Club - latest features and updates
|
|
|
|
|
|
VP
Status: There is always something new !!
Affiliations: PMI,QAI Global,eXampleCG
Joined: 08 May 2009
Posts: 1400
Followers: 8
Kudos [?]:
84
[0], given: 10
|
Re: odds and evens! [#permalink]
04 May 2011, 20:40
y-z = odd means either y is even and z is odd or vice versa. Hence A. yz = even means y,z even or y is even and z odd and viceversa. Thus A.
_________________
Visit -- http://www.sustainable-sphere.com/
Promote Green Business,Sustainable Living and Green Earth !!
|
|
|
|
|
|
GMAT Instructor
Joined: 24 Jun 2008
Posts: 973
Location: Toronto
Followers: 167
Kudos [?]:
443
[0], given: 3
|
Re: odds and evens! [#permalink]
05 May 2011, 15:00
AnkitK wrote: y and z are nin zero integers ,is the square of (y+z) even?
1.y-z is odd
2.yz is even As I posted in another thread a moment ago, positive integer exponents never matter in an even/odd question, so we can just ignore the 'square of' part of the question: it's just asking if y+z is even. Addition and subtraction follow the same odd/even rules, so if y-z is odd, then y+z is odd, and Statement 1 is sufficient. From Statement 2, y and z can both be even, in which case y+z is even, or one can be even and the other odd, in which case y+z is odd. So the answer is A.
_________________
Nov 2011: After years of development, I am now making my advanced Quant books and high-level problem sets available for sale. Contact me at ianstewartgmat at gmail.com for details.
Private GMAT Tutor based in Toronto
|
|
|
|
|
|
Director
Joined: 01 Feb 2011
Posts: 792
Followers: 11
Kudos [?]:
62
[0], given: 42
|
Re: odds and evens! [#permalink]
07 May 2011, 17:00
1. Sufficient
y-z is odd
=> either
y is even,z is odd or
y is odd ,z is even
in both the scenarios mentioned above y+z is odd = > (y+z)^ 2 is odd
2. Not sufficient
yz is even
atleast one of the above is even
when both y and z are even , given expression is even
but when y is odd and z is even , given expression is odd
Answer is A.
|
|
|
|
|
|
|
Re: odds and evens!
[#permalink]
07 May 2011, 17:00
|
|
|
|
|
|
|
|
|
Similar topics |
Author |
Replies |
Last post |
|
Similar
Topics:
|
 |
|
|
if x, y, and z are non zero integers and x>yz, which of
|
MA |
4 |
27 Jan 2005, 00:26 |
|
|
|
|
x+y+z is even, is x*y*z even? 1) x*y even 2) y*z odd
|
pb_india |
4 |
10 May 2005, 20:35 |
|
|
|
|
If W,X,Y, and Z are integers such that W/X and Y/Z are
|
ffgmat |
4 |
04 Feb 2006, 00:02 |
|
|
|
|
x, y, and z are integers, is xz even? 1) xy is even 2) yz is
|
getzgetzu |
4 |
06 May 2006, 04:57 |
|
|
|
|
If W,X,Y and Z are integers such that W/X and Y/Z are
|
zaz |
2 |
08 Apr 2009, 20:20 |
|
|
|
|
|
|
close
