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If xy > 0, does xy y = 3? (1) xy = 3 (2) y 1 = 0

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rxs0005
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If xy > 0, does xy y = 3? (1) xy = 3 (2) y 1 = 0 [#permalink] New post   04 Dec 2010, 03:10
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If xy > 0, does xy – y = 3?

(1) xy = 3
(2) y – 1 = 0
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A
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Bunuel
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Re: Algebra DS [#permalink] New post   04 Dec 2010, 03:22
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rxs0005 wrote:
If xy > 0, does xy – y = 3?

(1) xy = 3
(2) y – 1 = 0


If xy > 0, does xy – y = 3?

(1) xy = 3 --> question becomes: is \(3-y=3\)? or is \(y=0\)? Since given that \(xy>0\) (or the same \(xy=3\)) then it's clear that \(y\neq{0}\) so we have the answer NO. Sufficient.

(2) y – 1 = 0 --> question becomes: is \(x=4\)? We don't know that. Not sufficient.

Answer: A.
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Re: Algebra DS [#permalink] New post   04 Dec 2010, 04:21
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thanks great explanation
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Re: Algebra DS [#permalink] New post   19 Dec 2010, 22:22
Bunuel wrote:
rxs0005 wrote:
If xy > 0, does xy – y = 3?

(1) xy = 3
(2) y – 1 = 0


If xy > 0, does xy – y = 3?

(1) xy = 3 --> question becomes: is \(3-y=3\)? or is \(y=0\)? Since given that \(xy>0\) (or the same \(xy=3\)) then it's clear that \(y\neq{0}\) so we have the answer NO. Sufficient.
(2) y – 1 = 0 --> question becomes: is \(x=4\)? We don't know that. Not sufficient.

Answer: A.



Good Explanation....
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Re: Algebra DS [#permalink] New post   24 Jan 2011, 01:47
Bunuel wrote:
rxs0005 wrote:
If xy > 0, does xy – y = 3?

(1) xy = 3
(2) y – 1 = 0


If xy > 0, does xy – y = 3?

(1) xy = 3 --> question becomes: is \(3-y=3\)? or is \(y=0\)? Since given that \(xy>0\) (or the same \(xy=3\)) then it's clear that \(y\neq{0}\) so we have the answer NO. Sufficient.
(2) y – 1 = 0 --> question becomes: is \(x=4\)? We don't know that. Not sufficient.

Answer: A.


Great! With your explanations, I am getting better at seeing through the equations and manipulating them! Thanks Kudos!
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Re: If xy > 0, does xy y = 3? (1) xy = 3 (2) y 1 = 0 [#permalink] New post   03 Jul 2013, 04:01
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From (1), xy-y = 3-y ; this is equal to 3 only if y=0 , but since its given that xy =3 neither x nor y can be 0. Therefore, given (1) xy-y is not equal to 3. Sufficient.
(2) simplifies the question to is x-1=3 or is x=4 which cannot be answered with this information. Insufficient.
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Re: If xy > 0, does xy y = 3? (1) xy = 3 (2) y 1 = 0 [#permalink] New post   03 Jul 2013, 09:29
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rxs0005 wrote:
If xy > 0, does xy – y = 3?

(1) xy = 3
(2) y – 1 = 0



From the given statement xy>0, we can deduce that either x,y>0 or x,y< 0

St1 we have xy=3
possible values of x and y are

x=-1, y=-3, substituting in the given we get 3-(-3)=6 which is not equal to 3
x=3,y=1, we get 3-1= 2 not equal 3
x=9,y=1/3 3- 1/3= 8/3 not equal to 3

we can safely that say that for any values satisfying given st1 we do not have the expression value equal 3

Hence Option B,C,E ruled out

St 2, y-1=0-----> y=1
we know only the value of y and that x>0 which is not sufficient. In order to satisfy the given equation that is xy-y=3 value of x should be 4 which we are not sure of.

Hence Ans should be A :)

thanks
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If xy > 0, does xy – y = 3? [#permalink] New post   19 Sep 2017, 02:04
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If xy > 0 => Either x and y both +ve or both -ve. Also both x and y not equal to 0
Question : is xy – y = 3?

(1) xy = 3
=> if xy – y = 3 true => 3-y=3 => y=0
As by question stem we know x and y both r non zero numbers. So above statement cant be true
Sufficient

(2) y – 1 = 0

y – 1 = 0 => y=1
as xy >0 => x>0

=> xy – y = x-1 . No other information related to x given
Insufficient

Answer: A
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Re: If xy > 0, does xy – y = 3? [#permalink] New post   22 Oct 2019, 06:10
3 is a prime, so only 3*1 results in 3.
(1) Therefore, x must be 3 and y must be 1 or the other way around. In either case, subtracting y would change the result to non-3. So, A is sufficient.
(2) y equals 1, we have no information about x, so it is insufficient.
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Re: If xy > 0, does xy y = 3? (1) xy = 3 (2) y 1 = 0 [#permalink] New post   15 Jan 2022, 04:28
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Re: If xy > 0, does xy y = 3? (1) xy = 3 (2) y 1 = 0 [#permalink]
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