1. The problem is to compare the cost per litre of petrol for Kieran and Sophie to determine who pays more per litre. 2. The formula to find the cost per litre is: $$\text{Cost per litre} = \frac{\text{Total cost}}{\text{Number of litres}}$$ 3. Calculate Kieran's cost per litre: $$\frac{16.20}{12} = 1.35$$ So, Kieran pays 1.35 per litre. 4. Calculate Sophie's cost per litre: $$\frac{20.40}{17} = 1.2$$ So, Sophie pays 1.2 per litre. 5. Compare the two costs: Kieran pays 1.35 per litre, Sophie pays 1.2 per litre. 6. Conclusion: Kieran pays more per litre of petrol than Sophie.