4400 Higher June 2005 Paper 3 Q5
5 The probability that a person chosen at random has brown eyes is 0.45
The probability that a person chosen at random has green eyes is 0.12
(a) Work out the probability that a person chosen at random has either brown eyes or green eyes. (2)
250 people are to be chosen at random.
(b) Work out an estimate for the number of people who will have green eyes. (2)
| Scheme | Marks |
|---|---|
| 0.45 + 0.12 | M1 |
| 0.57 | A1 |
| (2) |
Notes
M1: For 0.45 + 0.12 or 1 − (0.45 + 0.12) or 1 − 0.45 − 0.12 or 0.43
A1: For 0.57 oe as final answer
| Scheme | Marks |
|---|---|
| 250 × 0.12 or 250 × 0.1 | M1 |
| 30 | A1 |
| (2) | |
| (4 marks) |
Notes
M1: For 250 × 0.12 or 250 × 0.1
A1: cao