4400 Higher November 2006 Paper 4 Q9
9 There are 48 beads in a bag.
Some of the beads are red and the rest of the beads are blue.
Shan is going to take a bead at random from the bag.
The probability that she will take a red bead is \(\dfrac{3}{8}\)
(a) Work out the number of red beads in the bag. (2)
Shan adds some red beads to the 48 beads in the bag.
The probability that she will take a red bead is now \(\dfrac{1}{2}\)
(b) Work out the number of red beads she adds. (2)
| Scheme | Marks |
|---|---|
| \(48 \times \frac{3}{8}\) | M1 |
| 18 | A1 |
| (2) |
Notes
A1: cao ans \(\frac{18}{48}\): M1A0
| Scheme | Marks |
|---|---|
| eg 48 − 18 − 18, \(x + 48 = 2(x + 18)\) | M1 |
| 12 | A1ft |
| (2) | |
| (4 marks) |
Notes
A1ft: ft from “18”