Hi everyone, how are you?

I don’t understand why the question below from PPP2 + doesn’t follow the probability rule printed below. The rule mentioned on the question prompt (ocurrence of event A = probability A occurring/probability A not occurring) is a specificity of **only** this question, correct? Thank you in advance!

The one on PP2 is talking about odds as a ratio of probabilities. Odds by itself is not a probability.