if x and y are integers, is xy even?
(1) x = y + 1
(2) x/y is an even integer
according to og, the solution is: D
Why is (1) sufficient? I mean, x could be 1 and y could be 0 --> xy would not be even, because xy = 0! but x could also be 2 and y=1, then xy=2 which is even! so for me, (1) is insufficient!
?
thx for hlp
OG12 #106: if x and y are integers, is xy even?
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- beatthegmatinsept
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Your logic on (a) is correct, except that in the only scenario where you get 0 as xy, that qualifies as an even integer as well. 0 is never considered odd, its considered even. I just googled it to confirmFractal wrote:if x and y are integers, is xy even?
(1) x = y + 1
(2) x/y is an even integer
according to og, the solution is: D
Why is (1) sufficient? I mean, x could be 1 and y could be 0 --> xy would not be even, because xy = 0! but x could also be 2 and y=1, then xy=2 which is even! so for me, (1) is insufficient!
?
thx for hlp
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- selango
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Check the properties for integer Zero in OG.Fractal wrote:if x and y are integers, is xy even?
(1) x = y + 1
(2) x/y is an even integer
according to og, the solution is: D
Why is (1) sufficient? I mean, x could be 1 and y could be 0 --> xy would not be even, because xy = 0! but x could also be 2 and y=1, then xy=2 which is even! so for me, (1) is insufficient!
?
thx for hlp
0 is even integer.
0 is neither positive nor odd.
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What if x=2 and y=4?
OG solution says they are consecutive but the question doesn't state that....
IMO Ans= B.
OG solution says they are consecutive but the question doesn't state that....
IMO Ans= B.
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- Brent@GMATPrepNow
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When posting questions, please use the spoiler function to hide the correct answer. This will allow others to attempt the question without seeing the final answer.Fractal wrote:if x and y are integers, is xy even?
(1) x = y + 1
(2) x/y is an even integer
Target question: Is xy even?
Aside: For xy to be even, we need x to be even, or y to be even (or both even).
Statement 1: x = y+1
This tells us that x is 1 greater than y.
This means that x and y are consecutive integers.
If x and y are consecutive integers, then one must be odd and the other must be even.
As such, the product xy must be even.
So, statement 1 is SUFFICIENT
Statement 2: x/y is an even integer.
If x/y is an even integer, then we can write x/y = 2k (where k is an integer)
Now take the equation and multiply both sides by y to get: x = 2ky
If k and y are both integers, we can see that 2ky (also known as x) must be even.
If x is even, then the product xy must be even.
So, statement 2 is SUFFICIENT
Answer = D
Cheers,
Brent
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