The distance between City R and City S was 860 km apart. A lorry travelled at an average speed of 100 km/h from City R to City S. At the same time, a sports car travelled at an average speed of 72 km/h from City S to City R. How much further did the lorry travel than the sports car when the lorry met the sports car on the way?
Combined speed of the lorry and the sports car
= 100 + 72
= 172 km/h
Time taken for the lorry and the sports car to meet
= 860 ÷ 172
= 5 h
Difference in the speed between the lorry and the sports car
= 100 - 72
= 28 km/h
Distance that the lorry travelled further than the sports car
= 5 x 28
= 140 km
Answer(s): 140 km