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nafiul9090
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nafiul9090 wrote:is X>0
i) xy>0
ii) X+Y>0
please help needed
(1) xy > 0 implies that both x and y should be positive or both x and y should be negative. This means x can be positive or negative. Since we don't have a unique answer, so (1) alone is NOT sufficient.
(2) x + y > 0 again implies that x can be positive or negative. So, (2) is alone is NOT sufficient.
Combining (1) and (2), we know that x and y, both cannot be negative because if both are negative then x + y < 0, which will be a contradiction. Example: x = -2, y = -3 implies xy = (-2)(-3) = 6 > 0 but x + y = -2 - 3 = -5 < 0.
Hence, we get that x and y have to be positive, or we can say that x > 0. SUFFICIENT.
The correct answer is C.
