At 7 a.m., Sam started from City C and travelled towards City D and his speed remained constant throughout. At 10 a.m., Abi started her journey from City C towards City D at an average speed of 76 km/h. Abi overtook Sam at 1 p.m. After overtaking, Abi carried on her journey at the same average speed and reached at City D at 4:30 p.m.
- Find Sam'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 Abi had travelled until Abi overtook Sam
= 3 x 76
= 228 km
From 7 a.m. to 1 p.m. = 6 h
Sam's average speed
= 228 ÷ 6
= 38 km/h
(b)
From 10 a.m. to 4:30 p.m. = 6 h 30 min
1 h = 60 min
6 h 30 min = 6
30 60
h = 6
12 h
Distance between the two cities
= 6
12 x 76
=
132 x 76
= 494 km
Answer(s): (a) 38 km/h; (b) 494 km