The distance between City Q and City R was 990 km apart. A lorry travelled at an average speed of 90 km/h from City Q to City R. At the same time, a car travelled at an average speed of 75 km/h from City R to City Q. 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
= 90 + 75
= 165 km/h
Time taken for the lorry and the car to meet
= 990 ÷ 165
= 6 h
Difference in the speed between the lorry and the car
= 90 - 75
= 15 km/h
Distance that the lorry travelled further than the car
= 6 x 15
= 90 km
Answer(s): 90 km