At 7 a.m., Vaidev started from City Q and travelled towards City R and his speed remained constant throughout. At 10 a.m., Dana started her journey from City Q towards City R at an average speed of 72 km/h. Dana overtook Vaidev at 1 p.m. After overtaking, Dana carried on her journey at the same average speed and reached at City R at 2:30 p.m.
- Find Vaidev's average speed in km/h.
- What is the distance between the two cities?
(a)
From 10 a.m. to 1 p.m. = 3 h
Distance that Dana had travelled until Dana overtook Vaidev
= 3 x 72
= 216 km
From 7 a.m. to 1 p.m. = 6 h
Vaidev's average speed
= 216 ÷ 6
= 36 km/h
(b)
From 10 a.m. to 2:30 p.m. = 4 h 30 min
1 h = 60 min
4 h 30 min = 4
30 60
h = 4
12 h
Distance between the two cities
= 4
12 x 72
=
92 x 72
= 324 km
Answer(s): (a) 36 km/h; (b) 324 km