At 7 a.m., Jack started from City G and travelled towards City H and his speed remained constant throughout. At 9 a.m., Jade started her journey from City G towards City H at an average speed of 72 km/h. Jade overtook Jack at 1 p.m. After overtaking, Jade carried on her journey at the same average speed and reached at City H at 2:20 p.m.

1. Find Jack'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 Jade had travelled until Jade overtook Jack
= 4 x 72
= 288 km

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

Jack's average speed
= 288 ÷ 6
= 48 km/h

(b)
From 9 a.m. to 2:20 p.m. = 5 h 20 min

1 h = 60 min
5 h 20 min = 5 ²⁰ ₆₀
 h = 5 ¹₃ h

Distance between the two cities
= 5 ¹₃ x 72
= ¹⁶₃ x 72
= 384 km

Answer(s): (a) 48 km/h; (b) 384 km