At 7 a.m., Vincent started from City C and travelled towards City D and his speed remained constant throughout. At 10 a.m., Opal started her journey from City C towards City D at an average speed of 72 km/h. Opal overtook Vincent at 1 p.m. After overtaking, Opal carried on her journey at the same average speed and reached at City D at 4:45 p.m.
- Find Vincent's average speed in km/h.
- What is the distance between the two cities?
(a)
From 10 a.m. to 1 p.m. = 3 h
Distance that Opal had travelled until Opal overtook Vincent
= 3 x 72
= 216 km
From 7 a.m. to 1 p.m. = 6 h
Vincent's average speed
= 216 ÷ 6
= 36 km/h
(b)
From 10 a.m. to 4:45 p.m. = 6 h 45 min
1 h = 60 min
6 h 45 min = 6
45 60
h = 6
34 h
Distance between the two cities
= 6
34 x 72
=
274 x 72
= 486 km
Answer(s): (a) 36 km/h; (b) 486 km