At 8 a.m., Jack started from City G and travelled towards City H and his speed remained constant throughout. At 9 a.m., Natalie started her journey from City G towards City H at an average speed of 72 km/h. Natalie overtook Jack at 2 p.m. After overtaking, Natalie carried on her journey at the same average speed and reached at City H at 4:40 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 2 p.m. = 5 h

Distance that Natalie had travelled until Natalie overtook Jack
= 5 x 72
= 360 km

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

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

(b)
From 9 a.m. to 4:40 p.m. = 7 h 40 min

1 h = 60 min
7 h 40 min = 7 ⁴⁰ ₆₀
 h = 7 ²₃ h

Distance between the two cities
= 7 ²₃ x 72
= ²³₃ x 72
= 552 km

Answer(s): (a) 60 km/h; (b) 552 km