At 7 a.m., Ahmad started from City P and travelled towards City Q and his speed remained constant throughout. At 10 a.m., Cindy started her journey from City P towards City Q at an average speed of 78 km/h. Cindy overtook Ahmad at 1 p.m. After overtaking, Cindy carried on her journey at the same average speed and reached at City Q at 3:30 p.m.
- Find Ahmad'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 Cindy had travelled until Cindy overtook Ahmad
= 3 x 78
= 234 km
From 7 a.m. to 1 p.m. = 6 h
Ahmad's average speed
= 234 ÷ 6
= 39 km/h
(b)
From 10 a.m. to 3:30 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 78
=
112 x 78
= 429 km
Answer(s): (a) 39 km/h; (b) 429 km