At 8 a.m., Sean started from City Y and travelled towards City Z and his speed remained constant throughout. At 10 a.m., Xandra started her journey from City Y towards City Z at an average speed of 72 km/h. Xandra overtook Sean at 2 p.m. After overtaking, Xandra carried on her journey at the same average speed and reached at City Z at 2:50 p.m.

1. Find Sean'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 Xandra had travelled until Xandra overtook Sean
= 4 x 72
= 288 km

From 8 a.m. to 2 p.m. = 6 h

Sean's average speed
= 288 ÷ 6
= 48 km/h

(b)
From 10 a.m. to 2:50 p.m. = 4 h 50 min

1 h = 60 min
4 h 50 min = 4 ⁵⁰ ₆₀
 h = 4 ⁵₆ h

Distance between the two cities
= 4 ⁵₆ x 72
= ²⁹₆ x 72
= 348 km

Answer(s): (a) 48 km/h; (b) 348 km