4MA0 Foundation January 2017 Paper 2R Q17
17 Here is a biased 4-sided spinner.
The spinner is spun.
The table shows the probability that the spinner lands on 1 and the probability that it lands on 2
| Number | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| Probability | 0.15 | 0.4 |
(a) Work out the probability that the spinner will not land on 1 (2)
(b) Work out the probability that the spinner will land on 1 or on 2 (1)
The probability that the spinner will land on 3 is twice the probability that the spinner will land on 4
(c) Work out the probability that the spinner will land on 3 (2)
Daljit is going to spin the spinner 160 times.
(d) Work out an estimate for the number of times the spinner will land on 2 (2)
| Scheme | Marks |
|---|---|
| 1 − 0.15 | M1 |
| 0.85 | A1 |
| (2) |
| Scheme | Marks |
|---|---|
| 0.55 | B1 |
| (1) |
| Scheme | Marks |
|---|---|
| \(\dfrac{1 - (0.15 + 0.4)}{3}\) or \(\dfrac{0.45}{3}\) (= 0.15) | M1 |
| 0.3 | A1 |
| (2) |
| Scheme | Marks |
|---|---|
| 160 × 0.4 | M1 |
| 64 | A1 |
| (2) | |
| (7 marks) |