At 9 a.m., Henry started from City Z and travelled towards City A and his speed remained constant throughout. At 10 a.m., Jean started her journey from City Z towards City A at an average speed of 66 km/h. Jean overtook Henry at 3 p.m. After overtaking, Jean carried on her journey at the same average speed and reached at City A at 5:30 p.m.

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

(a)
From 10 a.m. to 3 p.m. = 5 h

Distance that Jean had travelled until Jean overtook Henry
= 5 x 66
= 330 km

From 9 a.m. to 3 p.m. = 6 h

Henry's average speed
= 330 ÷ 6
= 55 km/h

(b)
From 10 a.m. to 5:30 p.m. = 7 h 30 min

1 h = 60 min
7 h 30 min = 7 ³⁰ ₆₀
 h = 7 ¹₂ h

Distance between the two cities
= 7 ¹₂ x 66
= ¹⁵₂ x 66
= 495 km

Answer(s): (a) 55 km/h; (b) 495 km