At 9 a.m., Oscar started from City M and travelled towards City N and his speed remained constant throughout. At 10 a.m., Gwen started her journey from City M towards City N at an average speed of 72 km/h. Gwen overtook Oscar at 1 p.m. After overtaking, Gwen carried on her journey at the same average speed and reached at City N at 3:45 p.m.

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

(a)
From 10 a.m. to 1 p.m. = 3 h

Distance that Gwen had travelled until Gwen overtook Oscar
= 3 x 72
= 216 km

From 9 a.m. to 1 p.m. = 4 h

Oscar's average speed
= 216 ÷ 4
= 54 km/h

(b)
From 10 a.m. to 3:45 p.m. = 5 h 45 min

1 h = 60 min
5 h 45 min = 5 ⁴⁵ ₆₀
 h = 5 ³₄ h

Distance between the two cities
= 5 ³₄ x 72
= ²³₄ x 72
= 414 km

Answer(s): (a) 54 km/h; (b) 414 km