At 9 a.m., Zeph started from City B and travelled towards City C and his speed remained constant throughout. At 10 a.m., Gem started her journey from City B towards City C at an average speed of 84 km/h. Gem overtook Zeph at 1 p.m. After overtaking, Gem carried on her journey at the same average speed and reached at City C at 3:20 p.m.

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

(a)
From 10 a.m. to 1 p.m. = 3 h

Distance that Gem had travelled until Gem overtook Zeph
= 3 x 84
= 252 km

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

Zeph's average speed
= 252 ÷ 4
= 63 km/h

(b)
From 10 a.m. to 3:20 p.m. = 5 h 20 min

1 h = 60 min
5 h 20 min = 5 ²⁰ ₆₀
 h = 5 ¹₃ h

Distance between the two cities
= 5 ¹₃ x 84
= ¹⁶₃ x 84
= 448 km

Answer(s): (a) 63 km/h; (b) 448 km