3 Maria chooses toast for her breakfast with probability 0.85 . If she does not choose toast then she has a bread roll. If she chooses toast then the probability that she will have jam on it is 0.8 . If she has a bread roll then the probability that she will have jam on it is 0.4 .
- Draw a fully labelled tree diagram to show this information.
- Given that Maria did not have jam for breakfast, find the probability that she had toast.