Level 3
A car uses 9 litres of petrol for every 50 km it travels at an average driving speed is 80 km/h. It uses 6 litres of petrol for every 70 km it travels when it average driving speed is 60 km/h. How much petrol will the car consume use for a journey which lasts 12 h if it travels at 80 km/h for 5 h and 60 km/h for the rest of the journey?
4 m