This graph shows the cost of petrol. It shows that 20 litres will cost £23 or £15 will buy 13 litres. Gradient = \(\frac{\text{change up}}{\text{change right}}\) or \(\frac{\text{change in y} ...

This graph shows the cost of petrol. It shows that 20 litres will cost £23 or £15 will buy 13 litres. Gradient = \(\frac{\text{change up}}{\text{change right}}\) or \(\frac{\text{change in y} ...