The distance between City M and City N was 840 km apart. A lorry travelled at an average speed of 90 km/h from City M to City N. At the same time, a convertible travelled at an average speed of 78 km/h from City N to City M. 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
= 90 + 78
= 168 km/h
Time taken for the lorry and the convertible to meet
= 840 ÷ 168
= 5 h
Difference in the speed between the lorry and the convertible
= 90 - 78
= 12 km/h
Distance that the lorry travelled further than the convertible
= 5 x 12
= 60 km
Answer(s): 60 km