Skip to content

Course home

2.3.3 Conditional probability (A-level only)

2.3.3 Conditional probability (A-level only)

MediumHard
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113
Question 46

A quality control inspector examines a batch of precision components. The probability that a component is 'Grade-A' (AAA) is 0.25, and the probability it is 'Grade-B' (BBB) is 0.75. The inspector selects two components at random, one after the other, with the first being replaced before the second is drawn.

a.

Calculate the probability that both components are of the same grade.

[2]
b.

Find the probability that both components are Grade-A, given that at least one of the components is Grade-A.

[3]
Markscheme

2.3.3 Conditional probability (A-level only) Questions

  1. A Level
  2. /Maths
  3. /2.3.3 Conditional probability (A-level only)

116 exam-style questions on OCR A Level Maths 2.3.3 Conditional probability (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

Question bank