At 09 25, Rachel left Town M and cycled towards Town N. Shiyun left Town M and cycled towards Town N at 09 55. Shiyun's cycling speed was 6 km/h faster than Rachel. At 11 25, Shiyun caught up with Rachel. Find the cycling speed of each cyclist.

1. Rachel
2. Shiyun

(a)
Duration that Shiyun cycled from 09 55 to 11 25
= 1³⁰₆₀
= 1¹₂ h

Distance that Shiyun cycled more than Rachel
= 1¹₂ x 6
= 9 km

However, since Rachel left 30 minutes earlier than Shiyun and Shiyun caught up with Rachel, it means that Rachel has cycled 9 km in 30 min.

1 h = 60 min 
30 min = 30 ÷ 60 = ¹₂ h

Rachel's cycling speed
= 9 ÷ ¹₂
= 9 x ²₁
= 18 km/h

(b)
Shiyun's cycling speed
= 18 + 6
= 24 km/h

Answer(s): (a) 18 km/h ; (b) 24 km/h