Can someone please explain how subtracting 1 from both sides in st 2 we get the below equation :bbaah wrote:Since we are interested in finding out if 1/k>0, we only need to isolate 1/k on one side of the inequalities in (1) and (2).
(1) 1/k - 1 > 0
=> 1/k > 1 (adding 1 to both sides of the inequality)
anything greater than 1 will also be greater than 0.
Sufficient.
(2) 1/k + 1 > 0
=> 1/k > -1 (subtracting 1 from both sides of the inequality)
If something is greater than -1, it could be -1/2, 0 , 1, 2, ...
So we cannot tell for sure if 1/k is greater than 0 (1/k = -1/2 <0, and 1/k = 1 >0)
Not Sufficient.
Statement 1 alone is Sufficient. A
=> 1/k > -1 (subtracting 1 from both sides of the inequality)
St 2 says:
1/k+1 > 0
Therefore,
Subtracting 1 from both sides
(1-1)/(k+1-1) > (0-1) => 0/k > -1 => 0 > -k
What am i doing wrong here ?
