At 8 a.m., George started from City A and travelled towards City B and his speed remained constant throughout. At 9 a.m., Tina started her journey from City A towards City B at an average speed of 80 km/h. Tina overtook George at 1 p.m. After overtaking, Tina carried on her journey at the same average speed and reached at City B at 5:15 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 Tina had travelled until Tina overtook George
= 4 x 80
= 320 km

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

George's average speed
= 320 ÷ 5
= 64 km/h

(b)
From 9 a.m. to 5:15 p.m. = 8 h 15 min

1 h = 60 min
8 h 15 min = 8 ¹⁵ ₆₀
 h = 8 ¹₄ h

Distance between the two cities
= 8 ¹₄ x 80
= ³³₄ x 80
= 660 km

Answer(s): (a) 64 km/h; (b) 660 km