15 In order to be accepted on a university course, a student needs to pass three exams.
The probability that the student passes the first exam is \(\frac { 3 } { 4 }\).
For each of the second and third exams, the probability of passing the exam is
- the same as the probability of passing the preceding exam if the student passed the preceding exam,
- half of the probability of passing the preceding exam if the student failed the preceding exam.
- Draw a tree diagram to represent the above information.
- Find the probability that the student passes all three exams.
- Find the probability that the student passes at least two of the exams.
- Find the probability that the student passes the third exam given that exactly two of the three exams are passed.