1MA0 Higher November 2015 Paper 1 Q4
4 There are some black pens, some blue pens, some red pens and some green pens in a box.
The table shows the probabilities that a pen taken at random from the box will be black or will be blue or will be red.
| colour | black | blue | red | green |
|---|---|---|---|---|
| probability | 0.3 | 0.2 | 0.4 |
There are 200 pens in the box.
(a) Work out the number of black pens in the box. (2)
A pen is taken at random from the box.
(b) Work out the probability that the pen will be green. (2)
| Answer | Mark | Notes |
|---|---|---|
| 60 | 2 | M1 for \(200 \times 0.3\) oe A1 cao |
| Answer | Mark | Notes |
|---|---|---|
| 0.1 | 2 | M1 subtracting sum of probabilities from 1, e.g. \(1 - (0.3 + 0.2 + 0.4)\) A1 cao |