At 9 a.m., Oscar started from City N and travelled towards City P and his speed remained constant throughout. At 10 a.m., Elyse started her journey from City N towards City P at an average speed of 80 km/h. Elyse overtook Oscar at 2 p.m. After overtaking, Elyse carried on her journey at the same average speed and reached at City P at 1:30 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 2 p.m. = 4 h

Distance that Elyse had travelled until Elyse overtook Oscar
= 4 x 80
= 320 km

From 9 a.m. to 2 p.m. = 5 h

Oscar's average speed
= 320 ÷ 5
= 64 km/h

(b)
From 10 a.m. to 1:30 p.m. = 3 h 30 min

1 h = 60 min
3 h 30 min = 3 ³⁰ ₆₀
 h = 3 ¹₂ h

Distance between the two cities
= 3 ¹₂ x 80
= ⁷₂ x 80
= 280 km

Answer(s): (a) 64 km/h; (b) 280 km