At 8 a.m., Simon started from City A and travelled towards City B and his speed remained constant throughout. At 10 a.m., Sarah started her journey from City A towards City B at an average speed of 78 km/h. Sarah overtook Simon at 2 p.m. After overtaking, Sarah carried on her journey at the same average speed and reached at City B at 4:30 p.m.
- Find Simon's average speed in km/h.
- What is the distance between the two cities?
(a)
From 10 a.m. to 2 p.m. = 4 h
Distance that Sarah had travelled until Sarah overtook Simon
= 4 x 78
= 312 km
From 8 a.m. to 2 p.m. = 6 h
Simon's average speed
= 312 ÷ 6
= 52 km/h
(b)
From 10 a.m. to 4:30 p.m. = 6 h 30 min
1 h = 60 min
6 h 30 min = 6
30 60
h = 6
12 h
Distance between the two cities
= 6
12 x 78
=
132 x 78
= 507 km
Answer(s): (a) 52 km/h; (b) 507 km