June 2010 2. An experiment consists of selecting a ball from a bag and spinning a coin. The bag contains 5 red balls and 7 blue balls. A ball is selected at random from the bag, its colour is noted and then the ball is returned to the bag. When a red ball is selected, a biased coin with probability of landing heads is spun. When a blue ball is selected a fair coin is spun. (a) Copy and complete the tree diagram below to show the possible outcomes and associated probabilities. (2) Shivani selects a ball and spins the appropriate coin. (b) Find the probability that she obtains a head. (2) that Tom selected a ball at random and obtained a head when he spun the appropriate coin, (c) find the probability that Tom selected a red ball. (3) Shivani and Tom each repeat this experiment. (d) Find the probability that the colour of the ball Shivani selects is the same as the colour of the ball Tom selects. (3)
June 2010 2. An experiment consists of selecting a ball from a bag and spinning a coin. The bag contains 5 red balls and 7 blue balls. A ball is selected at random from the bag, its colour is noted and then the ball is returned to the bag. When a red ball is selected, a biased coin with probability of landing heads is spun. When a blue ball is selected a fair coin is spun. (a) Copy and complete the tree diagram below to show the possible outcomes and associated probabilities. (2) Shivani selects a ball and spins the appropriate coin. (b) Find the probability that she obtains a head. (2) that Tom selected a ball at random and obtained a head when he spun the appropriate coin, (c) find the probability that Tom selected a red ball. (3) Shivani and Tom each repeat this experiment. (d) Find the probability that the colour of the ball Shivani selects is the same as the colour of the ball Tom selects. (3)
2-S1-Probability-Questions.docx