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2.3 Probability

2.3 Probability

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Question 68

A bag contains 10 blue counters, 8 red counters and 6 green counters.

Two counters are removed from the bag at random, one after the other, without replacement.

a.

Draw a tree diagram to represent this information.

[2]
b.

Find the probability that both counters removed are green.

[2]
c.

Given that at least one of the counters removed is red, find the probability that both counters are red.

[3]
Markscheme

2.3 Probability Questions

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

200 exam-style questions on OCR A Level Maths 2.3 Probability, covering 2.3.1 Mutually exclusive and independent events, 2.3.2 Diagrams to assist probability calculations, 2.3.3 Conditional probability (A-level only), 2.3.4 Conditional probability from first principles (A-level only), and 2.3.5 Modelling with probability. Each one has a worked solution and a mark scheme showing where the marks go.

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