At 7 a.m., Mark started from City K and travelled towards City L and his speed remained constant throughout. At 9 a.m., Raeann started her journey from City K towards City L at an average speed of 84 km/h. Raeann overtook Mark at 1 p.m. After overtaking, Raeann carried on her journey at the same average speed and reached at City L at 2:20 p.m.
- Find Mark's average speed in km/h.
- What is the distance between the two cities?
(a)
From 9 a.m. to 1 p.m. = 4 h
Distance that Raeann had travelled until Raeann overtook Mark
= 4 x 84
= 336 km
From 7 a.m. to 1 p.m. = 6 h
Mark's average speed
= 336 ÷ 6
= 56 km/h
(b)
From 9 a.m. to 2:20 p.m. = 5 h 20 min
1 h = 60 min
5 h 20 min = 5
20 60
h = 5
13 h
Distance between the two cities
= 5
13 x 84
=
163 x 84
= 448 km
Answer(s): (a) 56 km/h; (b) 448 km