At 7 a.m., Japheth started from City K and travelled towards City L and his speed remained constant throughout. At 9 a.m., Dana started her journey from City K towards City L at an average speed of 81 km/h. Dana overtook Japheth at 1 p.m. After overtaking, Dana carried on her journey at the same average speed and reached at City L at 6:40 p.m.

1. Find Japheth'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 Dana had travelled until Dana overtook Japheth
= 4 x 81
= 324 km

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

Japheth's average speed
= 324 ÷ 6
= 54 km/h

(b)
From 9 a.m. to 6:40 p.m. = 9 h 40 min

1 h = 60 min
9 h 40 min = 9 ⁴⁰ ₆₀
 h = 9 ²₃ h

Distance between the two cities
= 9 ²₃ x 81
= ²⁹₃ x 81
= 783 km

Answer(s): (a) 54 km/h; (b) 783 km