At 9 a.m., Dylan started from City D and travelled towards City E and his speed remained constant throughout. At 10 a.m., Emma started her journey from City D towards City E at an average speed of 72 km/h. Emma overtook Dylan at 1 p.m. After overtaking, Emma carried on her journey at the same average speed and reached at City E at 1:25 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 Emma had travelled until Emma overtook Dylan
= 3 x 72
= 216 km
From 9 a.m. to 1 p.m. = 4 h
Dylan's average speed
= 216 ÷ 4
= 54 km/h
(b)
From 10 a.m. to 1:25 p.m. = 3 h 25 min
1 h = 60 min
3 h 25 min = 3
25 60
h = 3
512 h
Distance between the two cities
= 3
512 x 72
=
4112 x 72
= 246 km
Answer(s): (a) 54 km/h; (b) 246 km