A motorist makes a journey from Singapore to Malacca to visit his in-laws, a journey of 240 km/h at an average speed of x km/h. Write down an expression for the number of hours taken for the journey. On his return journey from Malacca to Singapore his average speed is reduced by 6km/h due to heavy traffic flow at the causeway. write down an expression for the time taken for the return journey. If return journey takes 20 minutes longer, from an equation in x and solve it to find the average speed for each journey, giving your answer correct to two decimal places.