At 8 a.m., Xavier started from City A and travelled towards City B and his speed remained constant throughout. At 9 a.m., Gabby started her journey from City A towards City B at an average speed of 90 km/h. Gabby overtook Xavier at 2 p.m. After overtaking, Gabby carried on her journey at the same average speed and reached at City B at 3:30 p.m.

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

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

Distance that Gabby had travelled until Gabby overtook Xavier
= 5 x 90
= 450 km

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

Xavier's average speed
= 450 ÷ 6
= 75 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 90
= ¹³₂ x 90
= 585 km

Answer(s): (a) 75 km/h; (b) 585 km