City X and City Y were 294 km apart. A sedan travelled from City X towards City Y. At the same time, a lorry started from City Y to City X. After travelling 1
13 h, the two vehicles were still 126 km apart. If the ratio of the average speed of the lorry to that of the sedan was 4 : 5, find
- the average speed of the lorry.
- the time taken for them to meet travelling the rest of the journey. Express your answer in h.
(a)
Distance covered in 1
13 h by the two vehicles
= 294 - 126
= 168 km
Combined speed of the two vehicles
= 168 ÷
43 = 168 x
34 = 126 km/h
Average speed of the lorry : Average speed of the sedan = 4 : 5
4 u + 5 u = 9 u
9 u = 126
1 u = 126 ÷ 9 = 14
Average speed of the lorry
= 4 u
= 4 x 14
= 56 km/h
(b)
Time taken for the lorry and the sedan to meet travelling the rest of the journey
= 126 ÷ 126
= 1 h
Answer(s): (a) 56 km/h; (b) 1 h