IMO B.
1) X > Y
Taking x=10, y=7, xy=70
Taking x=2, y=1, xy=2
NOT SUFFICIENT
2) x^2 = y^2
=> x=y OR x=-y
So, xy = x^2 or -x^2
Since 70 is not a perfect square, answer is a definit NO
SUFFICIENT
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jimmiejaz
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IMO ans is E.
Nothing is given about x or y
From 1 we have x>y
take any value.
x=10,y=8 xy=80 (no)
x=10, y=7 xy=70 (yes)
insuff. eliminate A,D
From 2 we have x^2=y^2
or x= +y
we still can have any value. x can be sqrt(70) too.
in that case xy will indeed be 70. in other cases it will not be.
remember, we cant take x=-y because the eqn will not hold true as a square cant be negative.
Nothing is given about x or y
From 1 we have x>y
take any value.
x=10,y=8 xy=80 (no)
x=10, y=7 xy=70 (yes)
insuff. eliminate A,D
From 2 we have x^2=y^2
or x= +y
we still can have any value. x can be sqrt(70) too.
in that case xy will indeed be 70. in other cases it will not be.
remember, we cant take x=-y because the eqn will not hold true as a square cant be negative.
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srisl11
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IMO B
from st 2 , we get x= |y| or y = |x|
For any value of x (integer or fraction), xy = x|x| cannot be 70 since 70 is not a perfect square
Statement 1 : Here we need not know whether x>y or not (I know we shouldn't use " whether or not" but it just makes explanation easy
)
OA please
from st 2 , we get x= |y| or y = |x|
For any value of x (integer or fraction), xy = x|x| cannot be 70 since 70 is not a perfect square
Statement 1 : Here we need not know whether x>y or not (I know we shouldn't use " whether or not" but it just makes explanation easy
)OA please
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GMATters1001
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I'm going with C. The stem does not specify that x is an integer or fraction. (1) doesn't give us enough info. they could multiply to 70 or they could not (x=10, y=7 perhaps, perhaps not). (2) tells us that x and y would have to be the square root of 70, which is possible give than there are no constraints on x and y in the stem requiring that they are integers or fractions, but does not alone prove one way or the other. A, D and B are now eliminated, leaving C and E.
Taken together, we know that absolute value x must equal absolute value y AND that x is greater than y. So x=-y and vice versa since their squares equal eachother. So x and y have opposite signs and xy cannot be 70. SUFFICIENT.
Therefore C.
Taken together, we know that absolute value x must equal absolute value y AND that x is greater than y. So x=-y and vice versa since their squares equal eachother. So x and y have opposite signs and xy cannot be 70. SUFFICIENT.
Therefore C.
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vittalgmat
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cramya
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Stmt I
x>y
x=40 y=2
xy <> 70
TRUE
x=35 y = 2
xy=70
INSUFF
Stmt II
x^2 = y^2
x=+y or x=-y
x=2 y=2
xy <> 70
x=sqrt(70) y = sqrt(70)
xy = 70
INSUFF
Stmt I and II together
x>y
x^2 = y^2 (X=+Y OR X=-Y (or) Y=+X OR Y=-X)
Since x>y x has to be positive and y negative
xy cannot be 70
C) Agree with Gmaters.
Feruza,
Friendly request: If possible please post the OA using spoiler with the question.
Regards,
CR
x>y
x=40 y=2
xy <> 70
TRUE
x=35 y = 2
xy=70
INSUFF
Stmt II
x^2 = y^2
x=+y or x=-y
x=2 y=2
xy <> 70
x=sqrt(70) y = sqrt(70)
xy = 70
INSUFF
Stmt I and II together
x>y
x^2 = y^2 (X=+Y OR X=-Y (or) Y=+X OR Y=-X)
Since x>y x has to be positive and y negative
xy cannot be 70
C) Agree with Gmaters.
Feruza,
Friendly request: If possible please post the OA using spoiler with the question.
Regards,
CR
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abhishekbansal
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Hi
Can somebody explain me the explanation given ---
Since X > Y, therefore X = -Y
According to me, if we take the converse--
1.) X = Y or -Y
2.) X > Y
Taking X = -Y and substituting in 2.) we get, -Y > Y which cannot be true.
The same stands for X = Y and getting Y > Y which is again absurd
How did we arrive at the answer C ???? :roll:
Can somebody explain me the explanation given ---
Since X > Y, therefore X = -Y
According to me, if we take the converse--
1.) X = Y or -Y
2.) X > Y
Taking X = -Y and substituting in 2.) we get, -Y > Y which cannot be true.
The same stands for X = Y and getting Y > Y which is again absurd
How did we arrive at the answer C ???? :roll:
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Stuart@KaplanGMAT
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-Y > Y is always true when Y is negative.abhishekbansal wrote:Hi
Can somebody explain me the explanation given ---
Since X > Y, therefore X = -Y
According to me, if we take the converse--
1.) X = Y or -Y
2.) X > Y
Taking X = -Y and substituting in 2.) we get, -Y > Y which cannot be true.
The same stands for X = Y and getting Y > Y which is again absurd
How did we arrive at the answer C ???? :roll:
e.g. if y = -2, then it's true that -(-2) > -2.
You're 100% correct that Y > Y makes no sense, and that's exactly why the statements together are sufficient. Together, we know that x must be positive and y must be negative, and:
(+) * (-) = (-)
which means it's impossible for xy to equal 70. In other words, we get a definite "no" answer to the question, which means that (C) is the correct answer.
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
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jimmiejaz
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Hi Stuart,
thanks for the explanation. But i still have a doubt.
From 2nd statement we have x= +y
yes, both x and y can be sqrt(70) too.
But, if we take x=-y don't we get -y^2 which cant be posiible as its a square.
I am confused in this.
thanks for the explanation. But i still have a doubt.
From 2nd statement we have x= +y
yes, both x and y can be sqrt(70) too.
But, if we take x=-y don't we get -y^2 which cant be posiible as its a square.
I am confused in this.
What if i have not yet beat the beast, I know i will beat it!!!!!!!!
