At 7 a.m., Fred started from City A and travelled towards City B and his speed remained constant throughout. At 10 a.m., Min started her journey from City A towards City B at an average speed of 90 km/h. Min overtook Fred at 1 p.m. After overtaking, Min carried on her journey at the same average speed and reached at City B at 6:40 p.m.
- Find Fred'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 Fred
= 3 x 90
= 270 km
From 7 a.m. to 1 p.m. = 6 h
Fred's average speed
= 270 ÷ 6
= 45 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 90
=
263 x 90
= 780 km
Answer(s): (a) 45 km/h; (b) 780 km