At 7 a.m., John started from City A and travelled towards City B and his speed remained constant throughout. At 10 a.m., Jaslyn started her journey from City A towards City B at an average speed of 72 km/h. Jaslyn overtook John at 1 p.m. After overtaking, Jaslyn carried on her journey at the same average speed and reached at City B at 3:50 p.m.
- Find John'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 Jaslyn had travelled until Jaslyn overtook John
= 3 x 72
= 216 km
From 7 a.m. to 1 p.m. = 6 h
John's average speed
= 216 ÷ 6
= 36 km/h
(b)
From 10 a.m. to 3:50 p.m. = 5 h 50 min
1 h = 60 min
5 h 50 min = 5
50 60
h = 5
56 h
Distance between the two cities
= 5
56 x 72
=
356 x 72
= 420 km
Answer(s): (a) 36 km/h; (b) 420 km