At 7 a.m., John started from City Q and travelled towards City R and his speed remained constant throughout. At 9 a.m., Gillian started her journey from City Q towards City R at an average speed of 66 km/h. Gillian overtook John at 1 p.m. After overtaking, Gillian carried on her journey at the same average speed and reached at City R at 5:30 p.m.
- Find John'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 Gillian had travelled until Gillian overtook John
= 4 x 66
= 264 km
From 7 a.m. to 1 p.m. = 6 h
John's average speed
= 264 ÷ 6
= 44 km/h
(b)
From 9 a.m. to 5:30 p.m. = 8 h 30 min
1 h = 60 min
8 h 30 min = 8
30 60
h = 8
12 h
Distance between the two cities
= 8
12 x 66
=
172 x 66
= 561 km
Answer(s): (a) 44 km/h; (b) 561 km