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.
200 exam-style questions on OCR (MEI) A Level Maths 2.3 Probability, covering 2.3.1 Calculate the probability of an event, 2.3.2 Complementary events, 2.3.3 Expected frequency of an event, 2.3.4 Diagrams to calculate probabilities, 2.3.5 Mutually exclusive and independent events, 2.3.6 Add probabilities for mutually exclusive events, 2.3.7 Multiply probabilities for independent events, 2.3.8 Mutually exclusive and independent events (notation) (A-level only), 2.3.9 Venn diagrams for probabilities (A-level only), 2.3.10 Conditional probabilities (A-level only), and 2.3.11 Independence via conditional probability (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.