At 7 a.m., Jenson started from City M and travelled towards City N and his speed remained constant throughout. At 8 a.m., Sarah started her journey from City M towards City N at an average speed of 72 km/h. Sarah overtook Jenson at 1 p.m. After overtaking, Sarah carried on her journey at the same average speed and reached at City N at 2:35 p.m.

1. Find Jenson's average speed in km/h.
2. What is the distance between the two cities?

(a)
From 8 a.m. to 1 p.m. = 5 h

Distance that Sarah had travelled until Sarah overtook Jenson
= 5 x 72
= 360 km

From 7 a.m. to 1 p.m. = 6 h

Jenson's average speed
= 360 ÷ 6
= 60 km/h

(b)
From 8 a.m. to 2:35 p.m. = 6 h 35 min

1 h = 60 min
6 h 35 min = 6 ³⁵ ₆₀
 h = 6 ⁷₁₂ h

Distance between the two cities
= 6 ⁷₁₂ x 72
= ⁷⁹₁₂ x 72
= 474 km

Answer(s): (a) 60 km/h; (b) 474 km