At 07 20, Marion left Town F and cycled towards Town G. Hilda left Town F and cycled towards Town G at 07 50. Hilda's cycling speed was 4 km/h faster than Marion. At 12 20, Hilda caught up with Marion. Find the cycling speed of each cyclist.

1. Marion
2. Hilda

(a)
Duration that Hilda cycled from 07 50 to 12 20
= 4³⁰₆₀
= 4¹₂ h

Distance that Hilda cycled more than Marion
= 4¹₂ x 4
= 18 km

However, since Marion left 30 minutes earlier than Hilda and Hilda caught up with Marion, it means that Marion has cycled 18 km in 30 min.

1 h = 60 min 
30 min = 30 ÷ 60 = ¹₂ h

Marion's cycling speed
= 18 ÷ ¹₂
= 18 x ²₁
= 36 km/h

(b)
Hilda's cycling speed
= 36 + 4
= 40 km/h

Answer(s): (a) 36 km/h ; (b) 40 km/h