odds and prob

Question

The odds in favor of an event occurring are 4 to 5.  Find the probability of the event not occurring.

Answer 1

odds of an event occurring are 4 to 5

this means there are 4 ways that the event can occur and 5 ways that the event cannot occur

the probability that the event occurs is 4/9

the probability that the event does not occur is 5/9  (answer)