At 09 10, Diana left Town S and cycled towards Town T. Sabrina left Town S and cycled towards Town T at 09 40. Sabrina's cycling speed was 4 km/h faster than Diana. At 11 10, Sabrina caught up with Diana. Find the cycling speed of each cyclist.

1. Diana
2. Sabrina

(a)
Duration that Sabrina cycled from 09 40 to 11 10
= 1³⁰₆₀
= 1¹₂ h

Distance that Sabrina cycled more than Diana
= 1¹₂ x 4
= 6 km

However, since Diana left 30 minutes earlier than Sabrina and Sabrina caught up with Diana, it means that Diana has cycled 6 km in 30 min.

1 h = 60 min 
30 min = 30 ÷ 60 = ¹₂ h

Diana's cycling speed
= 6 ÷ ¹₂
= 6 x ²₁
= 12 km/h

(b)
Sabrina's cycling speed
= 12 + 4
= 16 km/h

Answer(s): (a) 12 km/h ; (b) 16 km/h