At 7 a.m., Carl started from City G and travelled towards City H and his speed remained constant throughout. At 9 a.m., Cathy started her journey from City G towards City H at an average speed of 90 km/h. Cathy overtook Carl at 1 p.m. After overtaking, Cathy carried on her journey at the same average speed and reached at City H at 4:20 p.m.

1. Find Carl'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 Cathy had travelled until Cathy overtook Carl
= 4 x 90
= 360 km

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

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

(b)
From 9 a.m. to 4:20 p.m. = 7 h 20 min

1 h = 60 min
7 h 20 min = 7 ²⁰ ₆₀
 h = 7 ¹₃ h

Distance between the two cities
= 7 ¹₃ x 90
= ²²₃ x 90
= 660 km

Answer(s): (a) 60 km/h; (b) 660 km