At 9 a.m., Ken started from City Z and travelled towards City A and his speed remained constant throughout. At 10 a.m., Yen started her journey from City Z towards City A at an average speed of 84 km/h. Yen overtook Ken at 1 p.m. After overtaking, Yen carried on her journey at the same average speed and reached at City A at 2:45 p.m.
- Find Ken'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 Yen had travelled until Yen overtook Ken
= 3 x 84
= 252 km
From 9 a.m. to 1 p.m. = 4 h
Ken's average speed
= 252 ÷ 4
= 63 km/h
(b)
From 10 a.m. to 2:45 p.m. = 4 h 45 min
1 h = 60 min
4 h 45 min = 4
45 60
h = 4
34 h
Distance between the two cities
= 4
34 x 84
=
194 x 84
= 399 km
Answer(s): (a) 63 km/h; (b) 399 km