arjunshn wrote:is n<0?
a)m<n
b)-n<m

1)n-m>0; not sufficient to answer the question.
2)n+m>0; not sufficient to answer the question.

now combining 1 and 2 we have 2n>0 i.e. n>0 hence 1 and 2 together are sufficient to answer the question..!! hence C

because it says n <0 you know it is a question revolving around positive/negative. so the question is is n negative?

1 - we dont' know what m is so can't be sufficient (BCE)

2 - still don't know what m is so (CE)

together you can try plugging in numbers using positive negative as a guide.

if m is 2 and n is 3 then 2 < 3 AND -3 < 2

Since we know we can make n positive, we have to try to make n negative:

if n is -10 and m is -11 then the first equation works but the second does not (10 is not < -11)

we can't try with a positive m becuase if n is negative then m must be negative and you notice that if m must be negative when n is negative then it will be impossible for the second statement to work - a positive will never be less than a negative therefore together they give you a consistent answer to the question and the answer is C.

Best of Luck