At 8 a.m., Jenson started from City G and travelled towards City H and his speed remained constant throughout. At 9 a.m., Risa started her journey from City G towards City H at an average speed of 90 km/h. Risa overtook Jenson at 2 p.m. After overtaking, Risa carried on her journey at the same average speed and reached at City H at 1:40 p.m.

1. Find Jenson'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 Risa had travelled until Risa overtook Jenson
= 5 x 90
= 450 km

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

Jenson's average speed
= 450 ÷ 6
= 75 km/h

(b)
From 9 a.m. to 1:40 p.m. = 4 h 40 min

1 h = 60 min
4 h 40 min = 4 ⁴⁰ ₆₀
 h = 4 ²₃ h

Distance between the two cities
= 4 ²₃ x 90
= ¹⁴₃ x 90
= 420 km

Answer(s): (a) 75 km/h; (b) 420 km