Foundation November 2023 Paper 2 Q11
11 A bag contains only red, green and blue counters.
- 8 of the counters are red.
- 15 of the counters are green.
- The rest of the counters are blue.
Sam chooses one counter at random from the bag.
The probability that this is a green counter is \(\dfrac{3}{8}\).
Work out the number of blue counters in the bag. [4]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 17 | 4 | B3 for 40 OR M2 for \(\frac{3}{8} = \frac{15}{n}\) or \(15 \div 3 \times 8\) or M1 for \(15 \div 3\) oe M1 for their 40 \(- (15 + 8)\) | Allow embedded calculation \(3 \times 5 = 15\) or list of multiples [3],6,9,12,15 with no extras |