At 8 a.m., Warren started from City L and travelled towards City M and his speed remained constant throughout. At 9 a.m., Emily started her journey from City L towards City M at an average speed of 90 km/h. Emily overtook Warren at 1 p.m. After overtaking, Emily carried on her journey at the same average speed and reached at City M at 4:40 p.m.
- Find Warren's average speed in km/h.
- What is the distance between the two cities?
(a)
From 9 a.m. to 1 p.m. = 4 h
Distance that Emily had travelled until Emily overtook Warren
= 4 x 90
= 360 km
From 8 a.m. to 1 p.m. = 5 h
Warren's average speed
= 360 ÷ 5
= 72 km/h
(b)
From 9 a.m. to 4:40 p.m. = 7 h 40 min
1 h = 60 min
7 h 40 min = 7
40 60
h = 7
23 h
Distance between the two cities
= 7
23 x 90
=
233 x 90
= 690 km
Answer(s): (a) 72 km/h; (b) 690 km