At 8 a.m., Lee started from City P and travelled towards City Q and his speed remained constant throughout. At 9 a.m., Zoe started her journey from City P towards City Q at an average speed of 84 km/h. Zoe overtook Lee at 2 p.m. After overtaking, Zoe carried on her journey at the same average speed and reached at City Q at 1:50 p.m.
- Find Lee's average speed in km/h.
- What is the distance between the two cities?
(a)
From 9 a.m. to 2 p.m. = 5 h
Distance that Zoe had travelled until Zoe overtook Lee
= 5 x 84
= 420 km
From 8 a.m. to 2 p.m. = 6 h
Lee's average speed
= 420 ÷ 6
= 70 km/h
(b)
From 9 a.m. to 1:50 p.m. = 4 h 50 min
1 h = 60 min
4 h 50 min = 4
50 60
h = 4
56 h
Distance between the two cities
= 4
56 x 84
=
296 x 84
= 406 km
Answer(s): (a) 70 km/h; (b) 406 km