Higher January 2021 Paper 1 Q14
14 Ding is going to play one game of snooker against each of two of his friends, Marco and Judd.
The probability tree diagram gives information about the probabilities that Ding will win or lose each of these two games.
(a) Work out the probability that Ding will win both games. (2)
(b) Work out the probability that Ding will win exactly one of the games. (3)
| Scheme | Marks |
|---|---|
| 0.6 × 0.9 | M1 |
| Correct answer scores full marks (unless from obvious incorrect working) Answer: 0.54 | A1 |
| (2) |
Notes
M1: oe
A1: oe e.g. \(\dfrac{27}{50}, \dfrac{54}{100}\), 54%
| Scheme | Marks |
|---|---|
| 0.6 × 0.1 (= 0.06) or 0.4 × 0.25 (= 0.1) or 0.4 × 0.75 (= 0.3) | M1 |
| 0.6 × 0.1 + 0.4 × 0.25 or 1 − (0.4 × 0.75) – “0.54” | M1 |
| Correct answer scores full marks (unless from obvious incorrect working) Answer: 0.16 | A1 |
| (3) | |
| (5 marks) |
Notes
M1: oe
M1: oe, ft their answer from (a)
A1: oe e.g. \(\dfrac{4}{25}, \dfrac{8}{50}, \dfrac{16}{100}\), 16%