At 7 a.m., Ryan started from City C and travelled towards City D and his speed remained constant throughout. At 9 a.m., Nora started her journey from City C towards City D at an average speed of 90 km/h. Nora overtook Ryan at 1 p.m. After overtaking, Nora carried on her journey at the same average speed and reached at City D at 2:30 p.m.
- Find Ryan'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 Nora had travelled until Nora overtook Ryan
= 4 x 90
= 360 km
From 7 a.m. to 1 p.m. = 6 h
Ryan's average speed
= 360 ÷ 6
= 60 km/h
(b)
From 9 a.m. to 2:30 p.m. = 5 h 30 min
1 h = 60 min
5 h 30 min = 5
30 60
h = 5
12 h
Distance between the two cities
= 5
12 x 90
=
112 x 90
= 495 km
Answer(s): (a) 60 km/h; (b) 495 km