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2.3 Probability

2.3 Probability

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Question 28

The events A A\,A and B B\,B are such that P(A)=310\displaystyle P(A) = \frac{3}{10}P(A)=103​, P(B)=45\displaystyle P(B) = \frac{4}{5}P(B)=54​ and P(A∣B)=14\displaystyle P(A|B) = \frac{1}{4}P(A∣B)=41​. Find

a.

P(A∩B)P(A \cap B)P(A∩B)

[2]
b.

P(B′∣A)P(B'|A)P(B′∣A)

[3]
c.

P(A′∪B)P(A' \cup B)P(A′∪B)

[2]
d.

Determine whether the events A A\,A and B B\,B 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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