At 8 a.m., Cody started from City X and travelled towards City Y and his speed remained constant throughout. At 9 a.m., Shiyun started her journey from City X towards City Y at an average speed of 80 km/h. Shiyun overtook Cody at 1 p.m. After overtaking, Shiyun carried on her journey at the same average speed and reached at City Y at 3:30 p.m.

1. Find Cody'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 Shiyun had travelled until Shiyun overtook Cody
= 4 x 80
= 320 km

From 8 a.m. to 1 p.m. = 5 h

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

(b)
From 9 a.m. to 3:30 p.m. = 6 h 30 min

1 h = 60 min
6 h 30 min = 6 ³⁰ ₆₀
 h = 6 ¹₂ h

Distance between the two cities
= 6 ¹₂ x 80
= ¹³₂ x 80
= 520 km

Answer(s): (a) 64 km/h; (b) 520 km