At 7 a.m., Fred started from City P and travelled towards City Q and his speed remained constant throughout. At 9 a.m., Opal started her journey from City P towards City Q at an average speed of 84 km/h. Opal overtook Fred at 1 p.m. After overtaking, Opal carried on her journey at the same average speed and reached at City Q at 5:45 p.m.
- Find Fred'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 Opal had travelled until Opal overtook Fred
= 4 x 84
= 336 km
From 7 a.m. to 1 p.m. = 6 h
Fred's average speed
= 336 ÷ 6
= 56 km/h
(b)
From 9 a.m. to 5:45 p.m. = 8 h 45 min
1 h = 60 min
8 h 45 min = 8
45 60
h = 8
34 h
Distance between the two cities
= 8
34 x 84
=
354 x 84
= 735 km
Answer(s): (a) 56 km/h; (b) 735 km