The probability of an event occurring is given Find the odds

The probability of an event occurring is given. Find the odds in favor of the event occurring.

0.45

Solution

There are only two possibilities:
with the event E will occur or it will not.
This means the probability of E occurring is 0.45

The probability of E not occurring is 0.55.

since the sum of all possible probabilities is 1.0.
.
Then the odds in favor of E occurring are
.
[probability E will occur]:[probability E will not occur] = 0.45:0.55 = 9:11