A delivery company uses three depots to distribute packages. Depot X handles 50% of the packages, Depot Y handles 30%, and Depot Z handles 20%.
If a package is handled by Depot X, the probability that it is delivered late is 4%. If a package is handled by Depot Y, the probability that it is delivered late is 5%. If a package is handled by Depot Z, the probability that it is delivered late is 10%.
Draw a tree diagram to represent this information.
A package is selected at random. Find the probability that it is delivered late.
Given that the package is delivered late, find the probability it was handled by Depot Z.
164 exam-style questions on WJEC A Level Maths 4.1 Probability (A-level only), covering 4.1.1 Probability (A-level only), 4.1.2 Probability (A-level only), and 4.1.3 Probability (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.