At 9 a.m., Valen started from City S and travelled towards City T and his speed remained constant throughout. At 10 a.m., Yen started her journey from City S towards City T at an average speed of 72 km/h. Yen overtook Valen at 3 p.m. After overtaking, Yen carried on her journey at the same average speed and reached at City T at 5:35 p.m.
- Find Valen's average speed in km/h.
- What is the distance between the two cities?
(a)
From 10 a.m. to 3 p.m. = 5 h
Distance that Yen had travelled until Yen overtook Valen
= 5 x 72
= 360 km
From 9 a.m. to 3 p.m. = 6 h
Valen's average speed
= 360 ÷ 6
= 60 km/h
(b)
From 10 a.m. to 5:35 p.m. = 7 h 35 min
1 h = 60 min
7 h 35 min = 7
35 60
h = 7
712 h
Distance between the two cities
= 7
712 x 72
=
9112 x 72
= 546 km
Answer(s): (a) 60 km/h; (b) 546 km