At 8 a.m., Zeph started from City E and travelled towards City F and his speed remained constant throughout. At 10 a.m., Kathy started her journey from City E towards City F at an average speed of 90 km/h. Kathy overtook Zeph at 1 p.m. After overtaking, Kathy carried on her journey at the same average speed and reached at City F at 1:50 p.m.

1. Find Zeph'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 Kathy had travelled until Kathy overtook Zeph
= 3 x 90
= 270 km

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

Zeph's average speed
= 270 ÷ 5
= 54 km/h

(b)
From 10 a.m. to 1:50 p.m. = 3 h 50 min

1 h = 60 min
3 h 50 min = 3 ⁵⁰ ₆₀
 h = 3 ⁵₆ h

Distance between the two cities
= 3 ⁵₆ x 90
= ²³₆ x 90
= 345 km

Answer(s): (a) 54 km/h; (b) 345 km