4MA0 Higher June 2015 Paper 4R Q6
6 The table shows the probabilities of people in Wales being in blood group O or in blood group A or in blood group AB.
| Blood group | Probability |
|---|---|
| O | 0.44 |
| A | 0.42 |
| B | |
| AB | 0.04 |
All people in Wales are in exactly one of the blood groups O, A, B or AB.
A person is selected at random from the people in Wales.
(a) Find the probability that this person is in blood group B. (2)
(b) Find the probability that this person is in blood group O or A. (1)
There are 1200 students in Aled’s school.
Aled’s school is in Wales.
(c) Work out an estimate for the number of pupils in Aled’s school who are in blood group AB. (2)
| Scheme | Marks |
|---|---|
| \(1 - 0.44 - 0.42 - 0.04\) or 1 − 0.9 | M1 |
| 0.1 oe | A1 |
| (2) |
Notes
A1: Accept \(\dfrac{1}{10}\) oe or 10 %
| Scheme | Marks |
|---|---|
| 0.86 oe | B1 |
| (1) |
Notes
B1: Accept \(\dfrac{86}{100}\) or \(\dfrac{43}{50}\) oe or 86 %
| Scheme | Marks |
|---|---|
| \(1200 \times 0.04\) | M1 |
| 48 | A1 |
| (2) |
Notes
A1: Accept 48 out of 1200
Note: M1A0 for 48/1200