At 8 a.m., Ben started from City Z and travelled towards City A and his speed remained constant throughout. At 9 a.m., Hilda started her journey from City Z towards City A at an average speed of 78 km/h. Hilda overtook Ben at 2 p.m. After overtaking, Hilda carried on her journey at the same average speed and reached at City A at 5:40 p.m.
- Find Ben's average speed in km/h.
- What is the distance between the two cities?
(a)
From 9 a.m. to 2 p.m. = 5 h
Distance that Hilda had travelled until Hilda overtook Ben
= 5 x 78
= 390 km
From 8 a.m. to 2 p.m. = 6 h
Ben's average speed
= 390 ÷ 6
= 65 km/h
(b)
From 9 a.m. to 5:40 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 78
=
263 x 78
= 676 km
Answer(s): (a) 65 km/h; (b) 676 km