OG 105

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OG 105

by anniev2 » Sat Mar 14, 2009 12:26 pm
Is |x| = y - z?

(1) x + y = z
(2) x < 0

OA IS C

Okay...

So from the given info in the question stem I understand that

x = y - z

OR

-x= -y + z


Statement 1

x + y = z Simplified: x = z - y
Since this simplifies to the same thing as a possible value of x I consider it SUFFICIENT because it is equivalent to -x. However, the explanation indicates that this statement is NOT SUFFICIENT.
Source: — Data Sufficiency |

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by cramya » Sat Mar 14, 2009 12:36 pm
So from the given info in the question stem I understand that

x = y - z
Its given

x = z-y


Help me understand how u got x = y-z from the info in stmt I

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by anniev2 » Sat Mar 14, 2009 1:46 pm
cramya wrote:
So from the given info in the question stem I understand that

x = y - z
Its given

x = z-y


Help me understand how u got x = y-z from the info in stmt I
I'm do not understand your question?...

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Re: OG 105

by Vemuri » Sun Mar 15, 2009 5:32 am
anniev2 wrote:Is |x| = y - z?

(1) x + y = z
(2) x < 0
Hi anniev2,

The question is basically asking if
x=y-z (or) x=z-y

Stmt 1: Not sufficient, because it does not solve for x=y-z.

Stmt 2: This alone does not help.

Combing both the statements, we know that x<0. So, x=y-z is the only possible solution.

I am not sure if my explanation is good enough. Can someone provide a better explanation?

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by cramya » Sun Mar 15, 2009 11:48 am
Stmt I

x+y = z

x = z-y

If z>y

z=5 y=3 x = 2

y-z = -2

|x| is not equal to y-z

If z<y

z=3 y=5 x=-2

|x| = y-z

INSUFF

Stmt II

x<0

No info on y and z

INSUFF


Together

x = z-y

x is negative

This means z<y therefore |x| will always be equal to y-z

SUFF

Choose C

Hope this helps; let me know if u still have questions.

Regards,
CR

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by Vemuri » Sun Mar 15, 2009 4:14 pm
perfecto !!! :) Thanks for the wonderful explanation.