At 7 a.m., Albert started from City P and travelled towards City Q and his speed remained constant throughout. At 8 a.m., Sabrina started her journey from City P towards City Q at an average speed of 78 km/h. Sabrina overtook Albert at 1 p.m. After overtaking, Sabrina carried on her journey at the same average speed and reached at City Q at 3:40 p.m.
- Find Albert's average speed in km/h.
- What is the distance between the two cities?
(a)
From 8 a.m. to 1 p.m. = 5 h
Distance that Sabrina had travelled until Sabrina overtook Albert
= 5 x 78
= 390 km
From 7 a.m. to 1 p.m. = 6 h
Albert's average speed
= 390 ÷ 6
= 65 km/h
(b)
From 8 a.m. to 3:40 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 78
=
233 x 78
= 598 km
Answer(s): (a) 65 km/h; (b) 598 km