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by crackgmat800 » Fri Jun 25, 2010 2:09 pm
If ☉ denotes a mathematical operation, does
x☉y=y☉x for all x and y?

(1) For all x and y, x☉y = 2(x2 + y2).
(2) For all y, 0☉y = 2 y2


Please explain. Will post OA later.
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Source: — Data Sufficiency |

by byby030384 » Fri Jun 25, 2010 3:38 pm
Answer: A.
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by selango » Fri Jun 25, 2010 9:49 pm
X☉Y=Y☉X

From stmt1,

X☉Y=2(X^2+Y^2)

Y☉X=2(Y^2+X^2)

Hence X☉Y=Y☉X

From stmt2,we cannot determine X

Hence A
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by crackgmat800 » Sat Jun 26, 2010 2:50 am
thanks..
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