4400 Higher November 2009 Paper 3 Q20
20 Each time Jeni plays a computer game the probability that she will win is \(\dfrac{2}{3}\)
Jeni plays the computer game 3 times.
Calculate the probability that Jeni will win
(a) all 3 games, (2)
(b) exactly 2 out of the 3 games. (3)
| Scheme | Marks |
|---|---|
| \((2/3)^3\) | M1 |
| 8/27 oe | A1 |
| (2) |
Notes
A1: 0.296.....
| Scheme | Marks |
|---|---|
| \((2/3)^2 \times 1/3 \times 3\) | M2 |
| 4/9 oe | A1 |
| (3) | |
| (5 marks) |
Notes
M2: M1 for \((2/3)^2 \times 1/3\) (= 4/27)
A1: 0.444....