CAIE S1 2004 November — Question 3

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2004
SessionNovember
TopicConditional Probability
TypeStandard Bayes with discrete events

3 When Andrea needs a taxi, she rings one of three taxi companies, A, B or C. 50\% of her calls are to taxi company \(A , 30 \%\) to \(B\) and \(20 \%\) to \(C\). A taxi from company \(A\) arrives late \(4 \%\) of the time, a taxi from company \(B\) arrives late \(6 \%\) of the time and a taxi from company \(C\) arrives late \(17 \%\) of the time.
  1. Find the probability that, when Andrea rings for a taxi, it arrives late.
  2. Given that Andrea's taxi arrives late, find the conditional probability that she rang company \(B\).