If the probability an event will occur is 1/2 determine a) the probability that the event will fail to occur

can someone help me with this? Not sure how to do it without the number of times the event occurred. I am confused If the probability an event will occur is 1/2 determine

a) the probability that the event will fail to occur.

b) the odds against the event occurring.

c) the odds in favor of the event occurring.

Explain your answer.

Thank you

a. P[fail to occur] = 1 - P[occur] = 1 - 1/2 = 1/2 <-------

b. odds against = unfavorable outcomes:favorable outcomes = 1:1

c. odds in favor = favorable outcomes:unfavorable outcomes = 1:1