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2.3 Probability

2.3 Probability

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Question 25

The events C C\,C and D D\,D are such that P(C)=25\displaystyle P(C) = \frac{2}{5}P(C)=52​, P(D)=34\displaystyle P(D) = \frac{3}{4}P(D)=43​ and P(C∣D)=13\displaystyle P(C|D) = \frac{1}{3}P(C∣D)=31​.

a.

Find P(C∩D)P(C \cap D)P(C∩D).

[2]
b.

Find P(D′∣C)P(D'|C)P(D′∣C).

[3]
c.

Find P(C′∪D)P(C' \cup D)P(C′∪D).

[2]
d.

Determine whether the events C C\,C and D D\,D are independent, give a reason for your answer.

[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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