At 8 a.m., Charlie started from City P and travelled towards City Q and his speed remained constant throughout. At 10 a.m., Anna started her journey from City P towards City Q at an average speed of 90 km/h. Anna overtook Charlie at 2 p.m. After overtaking, Anna carried on her journey at the same average speed and reached at City Q at 1:30 p.m.

1. Find Charlie'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 Anna had travelled until Anna overtook Charlie
= 4 x 90
= 360 km

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

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

(b)
From 10 a.m. to 1:30 p.m. = 3 h 30 min

1 h = 60 min
3 h 30 min = 3 ³⁰ ₆₀
 h = 3 ¹₂ h

Distance between the two cities
= 3 ¹₂ x 90
= ⁷₂ x 90
= 315 km

Answer(s): (a) 60 km/h; (b) 315 km