At 7 a.m., Asher started from City X and travelled towards City Y and his speed remained constant throughout. At 8 a.m., Xuan started her journey from City X towards City Y at an average speed of 72 km/h. Xuan overtook Asher at 1 p.m. After overtaking, Xuan carried on her journey at the same average speed and reached at City Y at 3:50 p.m.

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

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

Distance that Xuan had travelled until Xuan overtook Asher
= 5 x 72
= 360 km

From 7 a.m. to 1 p.m. = 6 h

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

(b)
From 8 a.m. to 3:50 p.m. = 7 h 50 min

1 h = 60 min
7 h 50 min = 7 ⁵⁰ ₆₀
 h = 7 ⁵₆ h

Distance between the two cities
= 7 ⁵₆ x 72
= ⁴⁷₆ x 72
= 564 km

Answer(s): (a) 60 km/h; (b) 564 km