A bag contains 6 red disks, 4 blue disks and 5 green disks. A fair dice has 4 faces painted red and 2 other faces painted blue.
Lisa takes a disk at random from the bag and records it's colour.m
Lisa then throws the dice twice and each time records the colour of the face it lands on.
Work out the probability that all three of the three colours Lisa records are red.
Thank you! xxxx
Maths probability help Watch
- Thread Starter
- 04-07-2016 13:32
- 04-07-2016 13:37
So you're working out the probability that the disk taken from the bag is red AND the face landed on the first dice is red AND the face landed on the second dice is red.
OR --- repeat for the other colours to get the final probability.
For and you multiply, add for OR.
- 04-07-2016 15:36
Let X be the number of red disks
P(X=3) = 3C3 * (2/5)^3 * (3/5)^3-3
P(X=3) = 2/5 * 2/5 * 2/5
- 04-07-2016 19:48
Never mind, answered better by other posters.