City J and City K were 495 km apart. A car travelled from City J towards City K. At the same time, a van started from City K to City J. After travelling 1
23 h, the two vehicles were still 270 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
23 h by the two vehicles
= 495 - 270
= 225 km
Combined speed of the two vehicles
= 225 ÷
53 = 225 x
35 = 135 km/h
Average speed of the van : Average speed of the car = 4 : 5
4 u + 5 u = 9 u
9 u = 135
1 u = 135 ÷ 9 = 15
Average speed of the van
= 4 u
= 4 x 15
= 60 km/h
(b)
Time taken for the van and the car to meet travelling the rest of the journey
= 270 ÷ 135
= 2 h
Answer(s): (a) 60 km/h; (b) 2 h