City B and City C were 324 km apart. A van travelled from City B towards City C. At the same time, a bus started from City C to City B. After travelling 1
25 h, the two vehicles were still 135 km apart. If the ratio of the average speed of the bus to that of the van was 4 : 5, find
- the average speed of the bus.
- the time taken for them to meet travelling the rest of the journey. Express your answer in h.
(a)
Distance covered in 1
25 h by the two vehicles
= 324 - 135
= 189 km
Combined speed of the two vehicles
= 189 ÷
75 = 189 x
57 = 135 km/h
Average speed of the bus : Average speed of the van = 4 : 5
4 u + 5 u = 9 u
9 u = 135
1 u = 135 ÷ 9 = 15
Average speed of the bus
= 4 u
= 4 x 15
= 60 km/h
(b)
Time taken for the bus and the van to meet travelling the rest of the journey
= 135 ÷ 135
= 1 h
Answer(s): (a) 60 km/h; (b) 1 h