OCR H240/02 2021 November — Question 12

Exam BoardOCR
ModuleH240/02 (Pure Mathematics and Statistics)
Year2021
SessionNovember
TopicTree Diagrams
TypeRepeated trials until stopping condition

12 Anika and Beth are playing a game which consists of several points.
  • The probability that Anika will win any point is 0.7 .
  • The probability that Beth will win any point is 0.3 .
  • The outcome of each point is independent of the outcome of every other point.
The first player to win two points wins the game.
  1. Write down the probability that the game consists of more than three points.
  2. Complete the probability tree diagram in the Printed Answer Booklet showing all the possibilities for the game.
  3. Determine the probability that Beth wins the game.
  4. Determine the probability that the game consists of exactly three points.
  5. Given that Beth wins the game, determine the probability that the game consists of exactly three points.