9709 P6 - Jun 2004 - Q6
2646
When Don plays tennis, 65% of his first serves go into the correct area of the court. If the first serve goes into the correct area, his chance of winning the point is 90%. If his first serve does not go into the correct area, Don is allowed a second serve, and of these, 80% go into the correct area. If the second serve goes into the correct area, his chance of winning the point is 60%. If neither serve goes into the correct area, Don loses the point.
- Draw a tree diagram to represent this information.
- Using your tree diagram, find the probability that Don loses the point.
- Find the conditional probability that Don’s first serve went into the correct area, given that he loses the point.
