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4.4 Probability (A-level only)

4.4 Probability (A-level only)

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Question 6

For two events R R\,R and SSS,

P(R∩S)=xP(R \cap S) = xP(R∩S)=x, P(R∩S′)=0.18P(R \cap S') = 0.18P(R∩S′)=0.18, P(R′∩S)=0.28P(R' \cap S) = 0.28P(R′∩S)=0.28, P(R′∩S′)=yP(R' \cap S') = yP(R′∩S′)=y

a.

Write down an expression for y y\,y in terms of xxx.

[1]
b.

Given that R R\,R and S S\,S are independent, show that x2−0.54x+0.0504=0x^{2} - 0.54x + 0.0504 = 0x2−0.54x+0.0504=0.

[3]
c.

Given also that P(R)<0.5P(R) < 0.5P(R)<0.5, find the value of x x\,x and the value of yyy.

[2]
Markscheme

4.4 Probability (A-level only) Questions

  1. A Level
  2. /Maths
  3. /4.4 Probability (A-level only)

164 exam-style questions on CCEA A Level Maths 4.4 Probability (A-level only), covering 4.4.1 Probability (A-level only), 4.4.2 Probability (A-level only), and 4.4.3 Probability (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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