At 7 a.m., Henry started from City L and travelled towards City M and his speed remained constant throughout. At 9 a.m., Eva started her journey from City L towards City M at an average speed of 78 km/h. Eva overtook Henry at 1 p.m. After overtaking, Eva carried on her journey at the same average speed and reached at City M at 3:30 p.m.

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

(a)
From 9 a.m. to 1 p.m. = 4 h

Distance that Eva had travelled until Eva overtook Henry
= 4 x 78
= 312 km

From 7 a.m. to 1 p.m. = 6 h

Henry's average speed
= 312 ÷ 6
= 52 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 78
= ¹³₂ x 78
= 507 km

Answer(s): (a) 52 km/h; (b) 507 km