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vivid007
Just gettin' started!
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 Posted: Mon Jan 21, 2008 10:09 am Post subject: integer.. |
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If x+y is an integer, is y an integer?
1) x-y is an integer.
2) x+2y is an integer.
The answer is B. but couldn't find my way out of this maze.
Please give me a way~!! |
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sankruth
Really wants to Beat The GMAT!
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| Posted: Mon Jan 21, 2008 10:37 am Post subject: |
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St 1
x - y is Integer
x = 1.5; y = 0.5
x+y = 2 (Int)
x-y = 1 (Int)
But y not Integer. So St1 INSUFF
St 2
x + 2y = (x + y) + y
(Integer + Non Integer) CANNOT add up to an Integer. Since (x + y) is Integer, s y must be an Integer.
SUFF, Hence B |
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preciousrain7
Rising GMAT Star
Joined: 06 Dec 2007
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Location: NYC, NY
Test Date: Jan 25th
Target GMAT Score: 700
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| Posted: Wed Jan 23, 2008 11:32 am Post subject: |
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| sankruth wrote: | St 1
x - y is Integer
x = 1.5; y = 0.5
x+y = 2 (Int)
x-y = 1 (Int)
But y not Integer. So St1 INSUFF
St 2
x + 2y = (x + y) + y
(Integer + Non Integer) CANNOT add up to an Integer. Since (x + y) is Integer, s y must be an Integer.
SUFF, Hence B |
How do you know that X+Y is an integer?
Using your equation:
(X+Y)+Y: what if X=1.5 and Y=.5, then the answer will end up being an integer... |
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sankruth
Really wants to Beat The GMAT!
Joined: 21 Oct 2007
Posts: 195
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Thanked 9 times in 9 posts
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| Posted: Wed Jan 23, 2008 11:35 am Post subject: |
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| Question stem says (x + y) is an Integer. |
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preciousrain7
Rising GMAT Star
Joined: 06 Dec 2007
Posts: 78
Thanks given: 9
Thanked 2 times in 2 posts
Location: NYC, NY
Test Date: Jan 25th
Target GMAT Score: 700
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| Posted: Wed Jan 23, 2008 12:03 pm Post subject: |
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| sankruth wrote: | | Question stem says (x + y) is an Integer. |
haha oops thanks! |
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