Given that P(A) = 1/4 , what are the odds against A occurring?

Question

I am not sure how to solve this.

Answer 1

If P(A) = 1/4 then P(not A) = 3/4

so odds against A = (3/4) : (1/4) = 3:1

Answer 2

P(certainty)=1
So P(A) + P(~A) = 1
What would be P(~A), i.e. probability of A not happening)?