DS

[ukr.net]

What is the value of k^2-k?
(1) The value of k - 1/k is 1.
(2) The value of 2k -1 is Square Root of 5

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient

ANS is D ???How to solve?

[camitava]

ukr.net,
From stmt - 1,
k - 1/k = 1
so k^2 - 1 = k
From stmt - 2,
2k - 1 = sqrt(5)
So k = (sqrt(5) + 1)^2/2

So IMO D. - Have u got me ukr.net?

[StarDust845]

Why is the answer D?

I see it this way.

From stmt (1) we get k^2 - k - 1 = 0

If you solve this, you get k = (1 + Sqrt(5))/2 or k = (1 - sqrt(5))/2
So the answer can't be A or D.

From stmt (2) we can solve for k which is k = (1 + sqrt(5))/2.

So answer MUST be B. What am I doing wrong?

Calista.

[jayhawk2001]

Why is the answer D?

I see it this way.

From stmt (1) we get k^2 - k - 1 = 0

If you solve this, you get k = (1 + Sqrt(5))/2 or k = (1 - sqrt(5))/2
So the answer can't be A or D.

We don't have to solve for k here. Question asks for k^2 - k.