At 7 a.m., Bobby 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 84 km/h. Hilda overtook Bobby at 1 p.m. After overtaking, Hilda carried on her journey at the same average speed and reached at City A at 2:45 p.m.
- Find Bobby'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 Hilda had travelled until Hilda overtook Bobby
= 4 x 84
= 336 km
From 7 a.m. to 1 p.m. = 6 h
Bobby's average speed
= 336 ÷ 6
= 56 km/h
(b)
From 9 a.m. to 2:45 p.m. = 5 h 45 min
1 h = 60 min
5 h 45 min = 5
45 60
h = 5
34 h
Distance between the two cities
= 5
34 x 84
=
234 x 84
= 483 km
Answer(s): (a) 56 km/h; (b) 483 km