The distance between City Q and City R was 810 km apart. A lorry travelled at an average speed of 83 km/h from City Q to City R. At the same time, a convertible travelled at an average speed of 79 km/h from City R to City Q. How much further did the lorry travel than the convertible when the lorry met the convertible on the way?
Combined speed of the lorry and the convertible
= 83 + 79
= 162 km/h
Time taken for the lorry and the convertible to meet
= 810 ÷ 162
= 5 h
Difference in the speed between the lorry and the convertible
= 83 - 79
= 4 km/h
Distance that the lorry travelled further than the convertible
= 5 x 4
= 20 km
Answer(s): 20 km