A distribution center receives electronics from three different suppliers. Supplier X provides 50% of the electronics, Supplier Y provides 30%, and Supplier Z provides 20%.
If an item comes from Supplier X, the probability it is damaged is 4%. If an item comes from Supplier Y, the probability it is damaged is 5%. If an item comes from Supplier Z, the probability it is damaged is 8%.
Draw a tree diagram to show this information.
An item is selected at random. Find the probability it is damaged.
Given that the item is damaged, find the probability it was from Supplier Z.
111 exam-style questions on WJEC A Level Maths 4.1.1 Probability (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.