The distance between City S and City T was 870 km apart. A lorry travelled at an average speed of 89 km/h from City S to City T. At the same time, a bus travelled at an average speed of 85 km/h from City T to City S. How much further did the lorry travel than the bus when the lorry met the bus on the way?
Combined speed of the lorry and the bus
= 89 + 85
= 174 km/h
Time taken for the lorry and the bus to meet
= 870 ÷ 174
= 5 h
Difference in the speed between the lorry and the bus
= 89 - 85
= 4 km/h
Distance that the lorry travelled further than the bus
= 5 x 4
= 20 km
Answer(s): 20 km