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2.3 Probability

2.3 Probability

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Question 15

Three car clubs are called Vintage (VVV), Supercar (SSS) and Classic (CCC).

No member belongs to both the Vintage club and the Classic club. Some members belong to both the Vintage club and the Supercar club, and some belong to both the Supercar club and the Classic club. No member belongs to all three clubs.

For a car owner chosen at random from a large town, the probabilities of the separate regions are

P(V∩S′)=0.24P(V \cap S') = 0.24P(V∩S′)=0.24, P(V∩S)=0.16P(V \cap S) = 0.16P(V∩S)=0.16, P(S∩V′∩C′)=0.12P(S \cap V' \cap C') = 0.12P(S∩V′∩C′)=0.12, P(S∩C)=aP(S \cap C) = aP(S∩C)=a, P(C∩S′)=0.15P(C \cap S') = 0.15P(C∩S′)=0.15, and the probability of belonging to none of the three clubs is bbb

a.

Explain why P(V∩C)=0P(V \cap C) = 0P(V∩C)=0.

[1]
b.

Given that P(V∣S)=P(V)P(V\mid S)=P(V)P(V∣S)=P(V), find the value of aaa.

[3]
c.

Find the value of bbb.

[2]
d.

Find P(V∣S′)P(V \mid S')P(V∣S′).

[2]
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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