DS Question please help

moonlite wrote:Is m not equal to n?

1) m + n < 0
2) mn < 0

OA is B

The explanation given is that since mn is negative one of the two numbers must be negative and the other positive.

BUT

can't we say that .5 x .5 = 0.25 which is also less than 0?

0.25 is greater than 0

Therefore statement B is sufficient as one number has to positive and one number has to be negative.

Hope this helps. Let me know if you have any doubts.

why isn't the answer D.

because looking at 1....

m+n < 0
therefore m < -n sufficient

or

n < -m sufficient

i.e. m does not equal n

am I missing something??

The answer is B- try not to overthink this one.

I) m + n < 0

m = -2
n = -1

-2 + -1 = -3 < 0; m is not equal to n

m = -2
n = -2

-2 + -2 = -4 < 0; m is equal to n; two answers are possible, insufficent

acerche, notice that m < -n and n < -m holds true in both these situations.

II) see Parellel Chase's explanation.

B