At 7 a.m., Bobby started from City E and travelled towards City F and his speed remained constant throughout. At 8 a.m., Tina started her journey from City E towards City F at an average speed of 78 km/h. Tina overtook Bobby at 1 p.m. After overtaking, Tina carried on her journey at the same average speed and reached at City F at 4:40 p.m.
- Find Bobby's average speed in km/h.
- What is the distance between the two cities?
(a)
From 8 a.m. to 1 p.m. = 5 h
Distance that Tina had travelled until Tina overtook Bobby
= 5 x 78
= 390 km
From 7 a.m. to 1 p.m. = 6 h
Bobby's average speed
= 390 ÷ 6
= 65 km/h
(b)
From 8 a.m. to 4:40 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