4MA0 Higher June 2015 Paper 4 Q1
1 A bag contains only red bricks and blue bricks.
There is a total of 20 bricks in the bag.
The probability that a brick taken at random from the bag will be red is \(\dfrac{2}{5}\)
How many blue bricks are there in the bag?
(3)
| Scheme | Marks |
|---|---|
| \(1 - \dfrac{2}{5}\) or \(\dfrac{3}{5}\) oe | M1 |
| \(\dfrac{3}{5} \times 20\) oe | M1 |
| 12 | A1 |
| (3) |
Notes
M1: or for \(\dfrac{2}{5} \times 20\) oe or 8 or \(\dfrac{8}{20}\)
M1: (dep) for 20 − '8'
A1: NB: \(\frac{12}{20}\) gains M2, A0