Positive number ?

[karthikpandian19]

Is K a positive number?
(1) |K^3| + 1 > K
(2) K + 1 > |K^3|

[rijul007]

Is K a positive number?
(1) |K^3| + 1 > K
(2) K + 1 > |K^3|

(1) |K^3| + 1 > K
|K^3| > K-1

for K=1
1>0

for K=-1
1>-2

Insufficient


(2) K + 1 > |K^3|

K+1 will always be positive

lets say |K^3| = 1/8
K+1 > 1/8
K > -7/8

Insufficient


Combinig the two statements

|K^3| -1 < K < |K^3| + 1

K=-1/2
1/8-1 < -1/2 < 1/8+1
-7/8 < -1/2 < 9/8

K=1
1-1 < 1 < 1+1
0 < 1 < 2

Insufficient

Option E

[karthikpandian19]

OA is E

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"Is K a positive number? (1) |K^3| + 1 ... > |K^3|"
The correct answer is E. Also a very confusing DS sum...
Explanation:

Statement 1:
When u put all the values (i) positive values (ii) negative values (iii) between 0 and 1 (iv) between -1 and 0 (v) also 0
the sign does not change in the equation at all, hence it becomes a bit confusing to choose but the answer is that the equation 1 is insufficient to answer the question
that whether K is a positive number or no

Statement 2:
When u put all the values (i) positive values (ii) negative values (iii) between 0 and 1 (iv) between -1 and 0 (v) also 0
In the above equation, when you put all the values you find that the equation does not accept any negative integers but it does take all the negative fractions, between -1 and 0
hence it becomes difficult to get that whether K is positive or negative.

Combined :
Since both of them accept negative values as well as positive values, i.e k between 0 and -1 so you cannot decide whether K is positive or negative.
Hence the correct answer is E.

[dvinoth86]

Awesome amit.
i ve made a note of the ranges that yu r using for DS problems..

Can you share other strategies for other sections as well??