The distance between City N and City P was 990 km apart. A lorry travelled at an average speed of 84 km/h from City N to City P. At the same time, a car travelled at an average speed of 81 km/h from City P to City N. 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
= 84 + 81
= 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
= 84 - 81
= 3 km/h
Distance that the lorry travelled further than the car
= 6 x 3
= 18 km
Answer(s): 18 km