At 7 a.m., Dylan started from City V and travelled towards City W and his speed remained constant throughout. At 10 a.m., Xandra started her journey from City V towards City W at an average speed of 72 km/h. Xandra overtook Dylan at 1 p.m. After overtaking, Xandra carried on her journey at the same average speed and reached at City W at 4:45 p.m.
- Find Dylan'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 Xandra had travelled until Xandra overtook Dylan
= 3 x 72
= 216 km
From 7 a.m. to 1 p.m. = 6 h
Dylan's average speed
= 216 ÷ 6
= 36 km/h
(b)
From 10 a.m. to 4:45 p.m. = 6 h 45 min
1 h = 60 min
6 h 45 min = 6
45 60
h = 6
34 h
Distance between the two cities
= 6
34 x 72
=
274 x 72
= 486 km
Answer(s): (a) 36 km/h; (b) 486 km