At 9 a.m., Vincent started from City U and travelled towards City V and his speed remained constant throughout. At 10 a.m., Min started her journey from City U towards City V at an average speed of 72 km/h. Min overtook Vincent at 1 p.m. After overtaking, Min carried on her journey at the same average speed and reached at City V at 6:40 p.m.
- Find Vincent's average speed in km/h.
- What is the distance between the two cities?
(a)
From 10 a.m. to 1 p.m. = 3 h
Distance that Min had travelled until Min overtook Vincent
= 3 x 72
= 216 km
From 9 a.m. to 1 p.m. = 4 h
Vincent's average speed
= 216 ÷ 4
= 54 km/h
(b)
From 10 a.m. to 6:40 p.m. = 8 h 40 min
1 h = 60 min
8 h 40 min = 8
40 60
h = 8
23 h
Distance between the two cities
= 8
23 x 72
=
263 x 72
= 624 km
Answer(s): (a) 54 km/h; (b) 624 km