4400 Higher November 2010 Paper 4 Q4
4 A bag contains some shapes.
Each shape is a circle or a triangle or a square.
Lewis takes at random a shape from the bag.
The probability that he will take a circle is 0.3
The probability that he will take a triangle is 0.1
(a) Work out the probability that he will take a square. (2)
(b) Work out the probability that he will take a shape with straight sides. (2)
Grace takes at random one of the shapes from the bag and then replaces the shape.
She does this 160 times.
(c) Work out an estimate for the number of times she will take a circle. (2)
| Scheme | Marks |
|---|---|
| 1 − (0.3 + 0.1) | M1 |
| 0.6 | A1 |
| (2) |
Notes
A1: cao
| Scheme | Marks |
|---|---|
| 0.1 + “0.6” or 1 − 0.3 | M1 |
| 0.7 | A1 |
| (2) |
Notes
M1: do not award if ans to (a) > 1
A1: ft from (a) if ans to (b) < 1
| Scheme | Marks |
|---|---|
| 0.3 × 160 | M1 |
| 48 | A1 |
| (2) | |
| (6 marks) |
Notes
M1: for 0.3 × 160 or 0.3 × 200 or \(\frac{48}{60}\)
A1: cao