At 8 a.m., Zane started from City M and travelled towards City N and his speed remained constant throughout. At 9 a.m., Jean started her journey from City M towards City N at an average speed of 78 km/h. Jean overtook Zane at 2 p.m. After overtaking, Jean carried on her journey at the same average speed and reached at City N at 5:40 p.m.

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

(a)
From 9 a.m. to 2 p.m. = 5 h

Distance that Jean had travelled until Jean overtook Zane
= 5 x 78
= 390 km

From 8 a.m. to 2 p.m. = 6 h

Zane's average speed
= 390 ÷ 6
= 65 km/h

(b)
From 9 a.m. to 5:40 p.m. = 8 h 40 min

1 h = 60 min
8 h 40 min = 8 ⁴⁰ ₆₀
 h = 8 ²₃ h

Distance between the two cities
= 8 ²₃ x 78
= ²⁶₃ x 78
= 676 km

Answer(s): (a) 65 km/h; (b) 676 km