City X and City Y were 352 km apart. A van travelled from City X towards City Y. At the same time, a lorry started from City Y to City X. After travelling 1
23 h, the two vehicles were still 132 km apart. If the ratio of the average speed of the lorry to that of the van was 5 : 6, find
- the average speed of the van.
- the time taken for them to meet travelling the rest of the journey. Express your answer in h.
(a)
Distance covered in 1
23 h by the two vehicles
= 352 - 132
= 220 km
Combined speed of the two vehicles
= 220 ÷
53 = 220 x
35 = 132 km/h
Average speed of the lorry : Average speed of the van = 5 : 6
5 u + 6 u = 11 u
11 u = 132
1 u = 132 ÷ 11 = 12
Average speed of the van
= 6 u
= 6 x 12
= 72 km/h
(b)
Time taken for the lorry and the van to meet travelling the rest of the journey
= 132 ÷ 132
= 1 h
Answer(s): (a) 72 km/h; (b) 1 h