9709 P61 - Nov 2011 - Q7
2670
Bag A contains 4 balls numbered 2, 4, 5, 8. Bag B contains 5 balls numbered 1, 3, 6, 8, 8. Bag C contains 7 balls numbered 2, 7, 8, 8, 8, 8, 9. One ball is selected at random from each bag.
- Find the probability that exactly two of the selected balls have the same number.
- Given that exactly two of the selected balls have the same number, find the probability that they are both numbered 2.
- Event X is ‘exactly two of the selected balls have the same number’. Event Y is ‘the ball selected from bag A has number 2’. Showing your working, determine whether events X and Y are independent or not.
