City B and City C were 315 km apart. A car travelled from City B towards City C. At the same time, a van started from City C to City B. After travelling 1
12 h, the two vehicles were still 126 km apart. If the ratio of the average speed of the van to that of the car was 4 : 5, 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
12 h by the two vehicles
= 315 - 126
= 189 km
Combined speed of the two vehicles
= 189 ÷
32 = 189 x
23 = 126 km/h
Average speed of the van : Average speed of the car = 4 : 5
4 u + 5 u = 9 u
9 u = 126
1 u = 126 ÷ 9 = 14
Average speed of the van
= 4 u
= 4 x 14
= 56 km/h
(b)
Time taken for the van and the car to meet travelling the rest of the journey
= 126 ÷ 126
= 1 h
Answer(s): (a) 56 km/h; (b) 1 h