Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and equations ensures a solution.
If |n + 5| = 5, what is the value of n?
(1) n^2 is not equal to 0.
(2) n^2 + 10n = 0.
Transforming the original codntiion we have n+5=-5,5, n=-10,0. Since there is 1 variable (n), we need 1 equation to match the number of variable and equation. Since there is 1 each in 1) and 2), D is likely the answer.
In case of 1), since n is not 0, n = 10 this is a unique answer and therefore is sufficient.
In case of 2), n(n+10)=0, n=0,-10 therefore it is not unique. Thus it is not sufficient.
The answer is A.
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