At 8 a.m., David started from City F and travelled towards City G and his speed remained constant throughout. At 10 a.m., Jen started her journey from City F towards City G at an average speed of 69 km/h. Jen overtook David at 2 p.m. After overtaking, Jen carried on her journey at the same average speed and reached at City G at 4:40 p.m.

1. Find David's average speed in km/h.
2. What is the distance between the two cities?

(a)
From 10 a.m. to 2 p.m. = 4 h

Distance that Jen had travelled until Jen overtook David
= 4 x 69
= 276 km

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

David's average speed
= 276 ÷ 6
= 46 km/h

(b)
From 10 a.m. to 4:40 p.m. = 6 h 40 min

1 h = 60 min
6 h 40 min = 6 ⁴⁰ ₆₀
 h = 6 ²₃ h

Distance between the two cities
= 6 ²₃ x 69
= ²⁰₃ x 69
= 460 km

Answer(s): (a) 46 km/h; (b) 460 km