At 9 a.m., Vincent started from City H and travelled towards City J and his speed remained constant throughout. At 10 a.m., Kylie started her journey from City H towards City J at an average speed of 72 km/h. Kylie overtook Vincent at 3 p.m. After overtaking, Kylie carried on her journey at the same average speed and reached at City J at 6:50 p.m.

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

(a)
From 10 a.m. to 3 p.m. = 5 h

Distance that Kylie had travelled until Kylie overtook Vincent
= 5 x 72
= 360 km

From 9 a.m. to 3 p.m. = 6 h

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

(b)
From 10 a.m. to 6:50 p.m. = 8 h 50 min

1 h = 60 min
8 h 50 min = 8 ⁵⁰ ₆₀
 h = 8 ⁵₆ h

Distance between the two cities
= 8 ⁵₆ x 72
= ⁵³₆ x 72
= 636 km

Answer(s): (a) 60 km/h; (b) 636 km