a( a – b )

[sumanr84]

If a^2/b=-8 , what is the value of a ( a - b ) ?

(1) a/b=-2

(2) a - b = 6

Statement (1) BY ITSELF is sufficient to answer the question, but statement (2) by itself is not.
Statement (2) BY ITSELF is sufficient to answer the question, but statement (1) by itself is not.
Statements (1) and (2) TAKEN TOGETHER are sufficient to answer the question, even though NEITHER statement BY ITSELF is sufficient.
EITHER statement BY ITSELF is sufficient to answer the question.
Statements (1) and (2) TAKEN TOGETHER are NOT sufficient to answer the question, requiring more data pertaining to the problem.

[spoiler]Kaplan CAT, OA:A[/spoiler]

[Rahul@gurome]

(1) a^2/b=-8 can be written as a.(a/b) = -8 or a.(-2) = -8 implies a = 4 and b = -2.
so, a(a - b) = 4(4+2) = 24
So, (1) is SUFFICIENT.

(2) a - b = 6 implies b = (a - 6)
So, a^2/b=-8 becomes a^2 = -8(a - 6) or a^2 + 8a - 48 = 0, which is quadratic in a.
Solving we get a = -12, 4 and b = -18 and -2.
We get 2 values of a(a - b) from these 2 values of a and b implies we don't get a unique answer.
So, (2) is NOT SUFFICIENT.

The correct answer is (A).

[this_time_i_will]

Please do not post DS problems in PS section.

a^2/b = -8.

I: a/b = -2.
so, a=4.
=>1/a = 4. we can find b also. so SUFFICIENT.

II: a-b=6
a^2=-8(a+6). This is a quadratic equation.This would give two values of a and hence we will have two values for b.
NOT SUFFICIENT.

A.

[outreach]

A

[sumanr84]

I missed..Moderators pls move it to DS section..