- Messages
- 69
- Reaction score
- 32
- Points
- 18
I need some help please.
November 2011, 61, Q7 part 3.
7. 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.
(i) Find the probability that exactly two of the selected balls have the same number. [5]
(ii) Given that exactly two of the selected balls have the same number, find the probability that they
are both numbered 2. [2]
(iii) 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.
I can't get how to get the P(X and Y) which is needed for part 3.
November 2011, 61, Q7 part 3.
7. 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.
(i) Find the probability that exactly two of the selected balls have the same number. [5]
(ii) Given that exactly two of the selected balls have the same number, find the probability that they
are both numbered 2. [2]
(iii) 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.
I can't get how to get the P(X and Y) which is needed for part 3.
