150 learner drivers recently took their driving test. Two-thirds of these people had taken 30 or more hours of driving lessons before their test.
Among the 99 drivers that passed the test, the ratio of those who had
taken 30 or more hours of lessons to those who hadn't was 10:1.
a) Use the information above to complete this frequency tree.
30 or more hours
Result
of lessons
Pass
Yes
Fail
150
No
Pass
9
Fail
b) Given that a learner driver has had fewer than 30 hours of lessons, use the
frequency tree to estimate the probability that they will pass their driving test
c) If another 60 people who have had fewer than 30 hours of driving lessons
were to take their driving test, estimate how many will pass