At 8 a.m., Ian started from City K and travelled towards City L and his speed remained constant throughout. At 9 a.m., Tiffany started her journey from City K towards City L at an average speed of 75 km/h. Tiffany overtook Ian at 1 p.m. After overtaking, Tiffany carried on her journey at the same average speed and reached at City L at 3:20 p.m.

1. Find Ian'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 Tiffany had travelled until Tiffany overtook Ian
= 4 x 75
= 300 km

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

Ian's average speed
= 300 ÷ 5
= 60 km/h

(b)
From 9 a.m. to 3:20 p.m. = 6 h 20 min

1 h = 60 min
6 h 20 min = 6 ²⁰ ₆₀
 h = 6 ¹₃ h

Distance between the two cities
= 6 ¹₃ x 75
= ¹⁹₃ x 75
= 475 km

Answer(s): (a) 60 km/h; (b) 475 km