At 9 a.m., Oscar started from City K and travelled towards City L and his speed remained constant throughout. At 10 a.m., Jaslyn started her journey from City K towards City L at an average speed of 72 km/h. Jaslyn overtook Oscar at 3 p.m. After overtaking, Jaslyn carried on her journey at the same average speed and reached at City L at 3:30 p.m.
- Find Oscar's average speed in km/h.
- What is the distance between the two cities?
(a)
From 10 a.m. to 3 p.m. = 5 h
Distance that Jaslyn had travelled until Jaslyn overtook Oscar
= 5 x 72
= 360 km
From 9 a.m. to 3 p.m. = 6 h
Oscar's average speed
= 360 ÷ 6
= 60 km/h
(b)
From 10 a.m. to 3:30 p.m. = 5 h 30 min
1 h = 60 min
5 h 30 min = 5
30 60
h = 5
12 h
Distance between the two cities
= 5
12 x 72
=
112 x 72
= 396 km
Answer(s): (a) 60 km/h; (b) 396 km