Is |x| = y – z?

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Is |x| = y – z?

by sanju09 » Thu Mar 22, 2012 12:38 am
Is |x| = y - z?
(1) x + y = z.
(2) x < 0.
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Source: — Data Sufficiency |

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by sam2304 » Thu Mar 22, 2012 12:55 am
1. x + y = z
x = z - y
-x = y - z
So |x| = y - z. SUFFICIENT

2. x < 0 -> no info about y and z. INSUFFICIENT.

IMO A.
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by killer1387 » Thu Mar 22, 2012 1:00 am
sanju09 wrote:Is |x| = y - z?
(1) x + y = z.
(2) x < 0.
C IMO

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by sanju09 » Thu Mar 22, 2012 1:15 am
(1) If x + y = z, then x = z - y and hence |x| = z - y if x > 0, OR |x| = y - z if x < 0. Insufficient

(2) If x < 0 then |x| > 0, but if it is equal to y - z or not, we never know. Insufficient

Taking (1) and (2) together, we can find that x = z - y and x < 0, and hence

[spoiler]YES to |x| = y - z.

Sufficient

Take C

@killer1387, please care giving explanations to your brilliant answers.
[/spoiler]
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com