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2.3 Probability

2.3 Probability

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Question 37

A jar contains 7 yellow marbles, 5 purple marbles, and 8 green marbles. Two marbles are selected at random from the jar without replacement.

a.

Draw a tree diagram to represent this information.

[3]
b.

Find the probability that both marbles selected are purple.

[2]
c.

Given that at least one of the marbles selected is yellow, find the probability that both marbles are yellow.

[3]
Markscheme

2.3 Probability Questions

  1. A Level
  2. /Maths
  3. /2.3 Probability

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.

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