At 7 a.m., Japheth started from City F and travelled towards City G and his speed remained constant throughout. At 8 a.m., Usha started her journey from City F towards City G at an average speed of 72 km/h. Usha overtook Japheth at 1 p.m. After overtaking, Usha carried on her journey at the same average speed and reached at City G at 2:25 p.m.

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

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

Distance that Usha had travelled until Usha overtook Japheth
= 5 x 72
= 360 km

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

Japheth's average speed
= 360 ÷ 6
= 60 km/h

(b)
From 8 a.m. to 2:25 p.m. = 6 h 25 min

1 h = 60 min
6 h 25 min = 6 ²⁵ ₆₀
 h = 6 ⁵₁₂ h

Distance between the two cities
= 6 ⁵₁₂ x 72
= ⁷⁷₁₂ x 72
= 462 km

Answer(s): (a) 60 km/h; (b) 462 km