Algebra

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Source: — Data Sufficiency |

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by pandeyvineet24 » Sun Oct 25, 2009 8:13 pm
i think the answer should be C.

stmt 1

rephrase, x - y = 1/2. - not sueff.
x = 3/2, y = 1 --> x-y =1/2 (x +ve, y +ve)
x = -1/2, y = -1 --> x-y = 1/2 (x -ve, y -ve)

stmt 2
x/y > 1, that means both x and y have same sign and x should be greater than y.

combine above 2 stmts. C should be the answer.

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Re: Algebra

by palvarez » Sun Oct 25, 2009 9:11 pm
heshamelaziry wrote:Are x and y both positive ?

(1) 2x - 2y = 1

(2) x/y > 1


Start with (2).

x/y > 1

(x/y) -1 > 0

(x-y)/y > 0
y(x-y)/y^2 > 0

y(x-y) > 0 Insufficient.

Use (1), x-y is +ve. Therefore, y is +ve.

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by heshamelaziry » Sun Oct 25, 2009 9:27 pm
pandeyvineet24 wrote:i think the answer should be C.

stmt 1

rephrase, x - y = 1/2. - not sueff.
x = 3/2, y = 1 --> x-y =1/2 (x +ve, y +ve)
x = -1/2, y = -1 --> x-y = 1/2 (x -ve, y -ve)

stmt 2
x/y > 1, that means both x and y have same sign and x should be greater than y.

combine above 2 stmts. C should be the answer.

Could you please elaborate on how both statements are sufficient ? Could you show what -ve values for x and y satisfy the restriction in statement 2 ?