The distance between London and York is 320 km. A train takes x hours to travel between London and York.

(a) Write down an expression, in terms of x, for the average speed of the train in km/h.

Answer ........................................ km/h

(b) A car takes 2.5 hours longer than a train to travel between London and York. The average speed of the train is 80 km/h greater than the average speed of the car. Form an equation in x and show that it simplifies to 2x² + 5x – 20 = 0