What is the value of Y

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Source: — Data Sufficiency |

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by coolly01 » Sun May 08, 2011 7:03 pm
champmag wrote:What is the value of y?

(1) 3|x^2 - 4| = y - 2

(2) |3 - y| = 11

OA after some discussion.
IMO: C
(1) tells us: y-2>0 -> y>2 => Insufficient
(2) tells us y = -8 or 14 => Insufficient
Combine
-> y=14 => sufficient
Thanks

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by cyrwr1 » Sun May 08, 2011 7:05 pm
C
Solve each statement and you get
1)y-2>=0 --->> y>=2
2)y= 14,-8

Hence,C
Last edited by cyrwr1 on Sun May 08, 2011 7:44 pm, edited 1 time in total.

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by champmag » Sun May 08, 2011 7:05 pm
Thanx guys..I got the point.

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by cyrwr1 » Sun May 08, 2011 7:07 pm
statement 1 can be rewritten as:

3*abs value= y -2
this part is positive or 0, add 2 on both sides.
positive + 2 =<y
Last edited by cyrwr1 on Sun May 08, 2011 7:46 pm, edited 1 time in total.

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by Stuart@KaplanGMAT » Sun May 08, 2011 7:40 pm
Just a quick point on solving absolute values, although it didn't turn out to make a difference to this particular question.

Remember, the absolute value of anything is non-negative; "non-negative" is NOT the same thing as positive.

So, if we solve a bit more precisely:

3*abs value = y - 2

0 <= y - 2

2 <= y

There could very well be questions on the GMAT in which the "or equal to" could be the difference between winning or losing the point.
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