If x, y, and z are integers and xy+z is an odd integer, is x an even integer?
1. xy+xz is an even integer
2. y+xz is an odd integer
Correct OA=A
Would appreciate a detailed solution.
Stumped
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Stumped would be right! Can u please confirm OA and source?
My approach
I am getting [spoiler]A)[/spoiler] (may be I am missing something and doing something incorrect in Stmt I ) but the OA is different
Given:- xy+z is an odd integer
Stmt I
xy+xz is an even integer
even integer - odd integer = odd integer
(xy+xz) - (xy+z) = odd integer
xy+xz-xy-z =odd
xz-z = odd
z(x-1) = odd
Both z and x-1 have to be odd
x-1 is odd then x has to be even
Definite YES
SUFF
Given: xy+z is an odd integer 1)
Stmt II
y+xz is an odd integer 2)
odd integer + odd intger = even integer
xy+z +y+xz = even
x(y+z) + y + z = even 3)
x->odd y->odd z->even
x-> even y->odd z->odd
2 possibilites still 1), 2) and 3) hold good
INSUFF
My approach
I am getting [spoiler]A)[/spoiler] (may be I am missing something and doing something incorrect in Stmt I ) but the OA is different
Given:- xy+z is an odd integer
Stmt I
xy+xz is an even integer
even integer - odd integer = odd integer
(xy+xz) - (xy+z) = odd integer
xy+xz-xy-z =odd
xz-z = odd
z(x-1) = odd
Both z and x-1 have to be odd
x-1 is odd then x has to be even
Definite YES
SUFF
Given: xy+z is an odd integer 1)
Stmt II
y+xz is an odd integer 2)
odd integer + odd intger = even integer
xy+z +y+xz = even
x(y+z) + y + z = even 3)
x->odd y->odd z->even
x-> even y->odd z->odd
2 possibilites still 1), 2) and 3) hold good
INSUFF
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muzali wrote:If x, y, and z are integers and xy+z is an odd integer, is x an even integer?
1. xy+xz is an even integer
2. y+xz is an odd integer
OA=A
Would appreciate a detailed solution.
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No problem, Muzali!Cramya, you are right. I had unwittingly put the incorrect OA. Source is GMATPrep.
IMO it could have got a little trickier and time consumung if u looked at it as x,y,z seperately without manipulations.
I am sure there are other better/equally good approaches and mine being just one of them.
Good question!
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Cramya,
Just amazed by your comprehending skills....
How on the earth could you get the idea of solving this monster ...kudos !!!
Just amazed by your comprehending skills....
How on the earth could you get the idea of solving this monster ...kudos !!!
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Bingo same approach same answer.cramya wrote:Stumped would be right! Can u please confirm OA and source?
My approach
I am getting [spoiler]A)[/spoiler] (may be I am missing something and doing something incorrect in Stmt I ) but the OA is different
Given:- xy+z is an odd integer
Stmt I
xy+xz is an even integer
even integer - odd integer = odd integer
(xy+xz) - (xy+z) = odd integer
xy+xz-xy-z =odd
xz-z = odd
z(x-1) = odd
Both z and x-1 have to be odd
x-1 is odd then x has to be even
Definite YES
SUFF
Given: xy+z is an odd integer 1)
Stmt II
y+xz is an odd integer 2)
odd integer + odd intger = even integer
xy+z +y+xz = even
x(y+z) + y + z = even 3)
x->odd y->odd z->even
x-> even y->odd z->odd
2 possibilites still 1), 2) and 3) hold good
INSUFF