At 7 a.m., Julian started from City H and travelled towards City J and his speed remained constant throughout. At 9 a.m., Jean started her journey from City H towards City J at an average speed of 69 km/h. Jean overtook Julian at 1 p.m. After overtaking, Jean carried on her journey at the same average speed and reached at City J at 6:20 p.m.
- Find Julian'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 Jean had travelled until Jean overtook Julian
= 4 x 69
= 276 km
From 7 a.m. to 1 p.m. = 6 h
Julian's average speed
= 276 ÷ 6
= 46 km/h
(b)
From 9 a.m. to 6:20 p.m. = 9 h 20 min
1 h = 60 min
9 h 20 min = 9
20 60
h = 9
13 h
Distance between the two cities
= 9
13 x 69
=
283 x 69
= 644 km
Answer(s): (a) 46 km/h; (b) 644 km