At 7 a.m., Ben started from City C and travelled towards City D and his speed remained constant throughout. At 9 a.m., Tiffany started her journey from City C towards City D at an average speed of 69 km/h. Tiffany overtook Ben at 1 p.m. After overtaking, Tiffany carried on her journey at the same average speed and reached at City D at 2:40 p.m.
- Find Ben'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 Tiffany had travelled until Tiffany overtook Ben
= 4 x 69
= 276 km
From 7 a.m. to 1 p.m. = 6 h
Ben's average speed
= 276 ÷ 6
= 46 km/h
(b)
From 9 a.m. to 2:40 p.m. = 5 h 40 min
1 h = 60 min
5 h 40 min = 5
40 60
h = 5
23 h
Distance between the two cities
= 5
23 x 69
=
173 x 69
= 391 km
Answer(s): (a) 46 km/h; (b) 391 km