From experience you know that 78% of students pass the statistics exam. Of those who pass the exam, 67% go on holiday after the results are posted. Those who fail usually want to study some more, but of those 25% holiday for a while anyway.

(a) Represent the individual probabilities using a probability tree.

(b) What is the probability that a student will go on holiday after the exam results are posted?

(c) You call up another student from the statistics class and hear on his answering machine, “I’m not home. I’m in Teneriffa!” What is the probability that he passed the statistics exam?