At 7 a.m., Carl started from City A and travelled towards City B and his speed remained constant throughout. At 9 a.m., Lynn started her journey from City A towards City B at an average speed of 84 km/h. Lynn overtook Carl at 1 p.m. After overtaking, Lynn carried on her journey at the same average speed and reached at City B 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 Lynn had travelled until Lynn overtook Carl
= 4 x 84
= 336 km

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

Carl's average speed
= 336 ÷ 6
= 56 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 84
= ²²₃ x 84
= 616 km

Answer(s): (a) 56 km/h; (b) 616 km