4400 Higher November 2005 Paper 4 Q7
7 Here is a four sided spinner.
Its sides are labelled 1, 2, 3 and 4
The spinner is biased.
The probability that the spinner lands on each of the numbers 1, 2 and 3 is given in the table.
| Number | Probability |
|---|---|
| 1 | 0.25 |
| 2 | 0.25 |
| 3 | 0.1 |
| 4 |
The spinner is spun once.
(a) Work out the probability that the spinner lands on 4 (2)
(b) Work out the probability that the spinner lands on either 2 or 3 (2)
| Scheme | Marks |
|---|---|
| 1 − (0.25 + 0.25 + 0.1) | M1 |
| 0.4 | A1 |
| (2) |
Notes
(1 − 0.51 = ) 0.49 : allow M1
| Scheme | Marks |
|---|---|
| 0.25 + 0.1 | M1 |
| 0.35 | A1 |
| (2) | |
| (4 marks) |
Notes
(0.25 + 0.1 = ) 0.26 : allow M1