At 7 a.m., George started from City J and travelled towards City K and his speed remained constant throughout. At 9 a.m., Cathy started her journey from City J towards City K at an average speed of 78 km/h. Cathy overtook George at 1 p.m. After overtaking, Cathy carried on her journey at the same average speed and reached at City K at 6:20 p.m.

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

(a)
From 9 a.m. to 1 p.m. = 4 h

Distance that Cathy had travelled until Cathy overtook George
= 4 x 78
= 312 km

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

George's average speed
= 312 ÷ 6
= 52 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 78
= ²⁸₃ x 78
= 728 km

Answer(s): (a) 52 km/h; (b) 728 km