At 7 a.m., Ryan started from City K and travelled towards City L and his speed remained constant throughout. At 9 a.m., Kimberly started her journey from City K towards City L at an average speed of 90 km/h. Kimberly overtook Ryan at 1 p.m. After overtaking, Kimberly carried on her journey at the same average speed and reached at City L at 1:40 p.m.

1. Find Ryan'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 Kimberly had travelled until Kimberly overtook Ryan
= 4 x 90
= 360 km

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

Ryan's average speed
= 360 ÷ 6
= 60 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) 60 km/h; (b) 420 km