4MA0 Higher January 2015 Paper 4 Q16
16 Chris and Sunil each take a driving test.
The probability that Chris passes the driving test is 0.9
The probability that Sunil passes the driving test is 0.65
(a) Complete the probability tree diagram.
(b) Work out the probability that exactly one of Chris or Sunil passes the driving test. (3)
| Scheme | Marks |
|---|---|
| 0.1 oe for Chris fail or 0.35 oe for Sunil fail | B1 |
| correct binary structure | B1 |
| ALL labels and values correct | B1 |
| (3) |
Notes
B1: stated or in correct position
B1: 4 branches needed on RHS
B1: accept P and F
| Scheme | Marks |
|---|---|
| 0.9 × “0.35” or “0.1” × 0.65 or 0.9 × 0.65 and 0.1 × 0.35 | M1 |
| 0.9 × “0.35” + “0.1” × 0.65 or 1 – (0.9×0.65 + 0.1×0.35) | M1 |
| 0.38 | A1 |
| (3) | |
| (6 marks) |
Notes
M1: complete method
A1: for 0.38 oe eg. \(\dfrac{19}{50}\)