At 7 a.m., Ian started from City P and travelled towards City Q and his speed remained constant throughout. At 9 a.m., Xandra started her journey from City P towards City Q at an average speed of 87 km/h. Xandra overtook Ian at 1 p.m. After overtaking, Xandra carried on her journey at the same average speed and reached at City Q at 1:40 p.m.
- Find Ian'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 Xandra had travelled until Xandra overtook Ian
= 4 x 87
= 348 km
From 7 a.m. to 1 p.m. = 6 h
Ian's average speed
= 348 ÷ 6
= 58 km/h
(b)
From 9 a.m. to 1:40 p.m. = 4 h 40 min
1 h = 60 min
4 h 40 min = 4
40 60
h = 4
23 h
Distance between the two cities
= 4
23 x 87
=
143 x 87
= 406 km
Answer(s): (a) 58 km/h; (b) 406 km