ninomoi wrote:
If n is an integer, is \(-3x^n\) positive?
(1) x is negative.
(2) n is odd.
Given: n = Integer
Question : \(-3x^n\) > 0 ?
Or, Is -3 * x^n > 0 ?
Or, Is x^n > 0 ?
St 1: x < 0, but we don't know whether "n" is even or odd.
If "n" is even the answer to the question is YES
If "n" is odd the answer to the question is NO (Insufficient)
St 2: n is odd, we don't know "x" is positive or negative.If "x" is positive the answer to the question is YES
If "x" is negative the answer to the question is NO (Insufficient)
Combining both statements we get,x is -ve and n is odd, therefore we can say that x^n < 0 always.
Answer to the question is "NO"
Sufficient (C)
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