I would say A
With positive integer:
1) Sufficient
If you multiply Y by itself several times and get to a number X, of course, X is a multpile of Y...
E.g.: 3 * 2^2 + 7 * 2 = 12 + 14 = 26 --> 26 is a multiple of 2
(2) Not sufficient
With this one, we can still have both cases
X=3 --> x^2 - x = 9 - 3 = 6
--> Let's say Y = 3 --> OK, the answer (6) is a multiple of Y
--> X is a multiple of Y
--> Let's say Y = 6 --> OK, the answer (6) is a multiple of Y
--> X is NOT a multiple of Y
This would be my answer...
GMAT PREP?? ANOTHER ONE.
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akshatsingh
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a) 3y^2+7y=x
y(3y+7)=x
since x and y are both integers, (3y+7) is an integer, say N.
we can say, y*N=x
Clearly N being an integer, (N times y)=x
Hence x is a multiple of y
SUFFICIENT
b) x^2-x is a multiple of y.
Or, Mx is a multiple of y. Clearly y is a multiple of x but nothing can be clearly said about x being a multiple of y.
NOT SUFFICIENT
My answer is A
Cheers!
Aks
y(3y+7)=x
since x and y are both integers, (3y+7) is an integer, say N.
we can say, y*N=x
Clearly N being an integer, (N times y)=x
Hence x is a multiple of y
SUFFICIENT
b) x^2-x is a multiple of y.
Or, Mx is a multiple of y. Clearly y is a multiple of x but nothing can be clearly said about x being a multiple of y.
NOT SUFFICIENT
My answer is A
Cheers!
Aks
