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arjtryarjtry
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If x^2-y^2=2, x=? (1) y^2=1 (2) x+y=1 A. Statement (1) ALONE 28 Jul 2008, 02:51
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If x^2-y^2=2, x=?
(1) y^2=1
(2) x+y=1
A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient.
B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient.
C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient.
D. Each Statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.



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If x^2-y^2=2, x=? (1) y^2=1 (2) x+y=1 A. Statement (1) ALONE 28 Jul 2008, 03:04
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X^2-Y^2=1

1). y^=1. => X^2=1 => x=1 or x=-1. Insuff.

2) x+y=1
X^2-Y^2=1 => (x+y)(x-y) =1 => x-y=1

now using x+y=1 and x-y=1, solve for x. you get x=1. sufficient.

Ans=B
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If x^2-y^2=2, x=? (1) y^2=1 (2) x+y=1 A. Statement (1) ALONE 28 Jul 2008, 05:27
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i get B as well. You do get an answer using stat 1, but there are two possible values, so its not sufficient on its own
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If x^2-y^2=2, x=? (1) y^2=1 (2) x+y=1 A. Statement (1) ALONE 28 Jul 2008, 06:39
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arjtryarjtry
If x^2-y^2=2, x=?
(1) y^2=1
(2) x+y=1
A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient.
B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient.
C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient.
D. Each Statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
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1)
x^2-y^2=2
--> x^2-1=2
--> x^2=3 --> x = + root (3) or - root(3)

2) x^2-y^2=2 --> (x+y)(x-y)=2
--> x-y=2 .
---> x+y=1
--> 2x=3
--> x=3/2

B is answer
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If x^2-y^2=2, x=? (1) y^2=1 (2) x+y=1 A. Statement (1) ALONE 28 Jul 2008, 07:58
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arjtryarjtry
If x^2-y^2=2, x=?
(1) y^2=1
(2) x+y=1
A. Statement (1) ALONE is sufficient but Statement (2) ALONE is not sufficient.
B. Statement (2) ALONE is sufficient but Statement (1) ALONE is not sufficient.
C. BOTH Statements TOGETHER are sufficient, but NEITHER Statement alone is sufficient.
D. Each Statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Show more

(1)
y^2=1
x^2 -1 = 2
x^2 = 3
x = 3^0.5 or - 3^0.5
so, Not Suff

(2) x+y=1 ---- (eq A)
x^2-y^2=2
(x+y)(x-y)=2
x-y=2
y=x-2 ---- (eq B)
Sub eq B in eq A, we got
x + x -2 = 1
2x = 3
x = 3/2
so Suff

Ans B



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