The distance between City B and City C was 720 km apart. A lorry travelled at an average speed of 100 km/h from City B to City C. At the same time, a car travelled at an average speed of 80 km/h from City C to City B. How much further did the lorry travel than the car when the lorry met the car on the way?
Combined speed of the lorry and the car
= 100 + 80
= 180 km/h
Time taken for the lorry and the car to meet
= 720 ÷ 180
= 4 h
Difference in the speed between the lorry and the car
= 100 - 80
= 20 km/h
Distance that the lorry travelled further than the car
= 4 x 20
= 80 km
Answer(s): 80 km