Data Sufficiency

Hi,

I came upon this data sufficiency problem in the Manhattan GMAT Cat 2.
I am trying to understand the explanation provided but no luck so far. Can anyone help me out? Is this some basic concept I have missed out on?

Thanks! Here is the question....The underlined sentence is what confuses me and is something I cannot understand.

Q What is the value of y?
(1) 3|x^2 -4| = y - 2
(2) |3 - y| = 11

A (1) INSUFFICIENT: Since this equation contains two variables, we cannot determine the value of y. We can, however, note that the absolute value expression |x^2 -4| must be greater than or equal to 0. Therefore, 3|x^2 -4| must be greater than or equal to 0, which in turn means that y - 2 must be greater than or equal to 0. If y - 2 > 0, then y > 2.[/b]

the explanation means that because |x| is greater than or equal to 0 for any real number x, S1:y - 2= 3|x^2 -4|is greater than or equal to 0. so, y is greater than or equal to 2. but as we don't know the value of x, we cannot know the exact value of y.
insufficient

S2: |3 - y| = 11
so
3-y=11 or -11
y=-8 or 14

can't determine which one is the value of y
insufficient

S1S2
toghther:
y=-8 or 14
and y is greater than or equal to 2

so y=14
sufficient

choose C

Excellent question....
Initially i went for E...but JJJooe's expl seems to be perfect.

KK9_GMAT wrote:Hi,

I came upon this data sufficiency problem in the Manhattan GMAT Cat 2.
I am trying to understand the explanation provided but no luck so far. Can anyone help me out? Is this some basic concept I have missed out on?

Thanks! Here is the question....The underlined sentence is what confuses me and is something I cannot understand.

Q What is the value of y?
(1) 3|x^2 -4| = y - 2
(2) |3 - y| = 11

A (1) INSUFFICIENT: Since this equation contains two variables, we cannot determine the value of y. We can, however, note that the absolute value expression |x^2 -4| must be greater than or equal to 0. Therefore, 3|x^2 -4| must be greater than or equal to 0, which in turn means that y - 2 must be greater than or equal to 0. If y - 2 > 0, then y > 2.[/b]

This will be E

vikram_k51 wrote:

KK9_GMAT wrote:Hi,

I came upon this data sufficiency problem in the Manhattan GMAT Cat 2.
I am trying to understand the explanation provided but no luck so far. Can anyone help me out? Is this some basic concept I have missed out on?

Thanks! Here is the question....The underlined sentence is what confuses me and is something I cannot understand.

Q What is the value of y?
(1) 3|x^2 -4| = y - 2
(2) |3 - y| = 11

A (1) INSUFFICIENT: Since this equation contains two variables, we cannot determine the value of y. We can, however, note that the absolute value expression |x^2 -4| must be greater than or equal to 0. Therefore, 3|x^2 -4| must be greater than or equal to 0, which in turn means that y - 2 must be greater than or equal to 0. If y - 2 > 0, then y > 2.[/b]

This will be E

1 more for E