At 09 10, Ivory left Town Z and cycled towards Town A. Barbara left Town Z and cycled towards Town A at 09 40. Barbara's cycling speed was 6 km/h faster than Ivory. At 12 10, Barbara caught up with Ivory. Find the cycling speed of each cyclist.

1. Ivory
2. Barbara

(a)
Duration that Barbara cycled from 09 40 to 12 10
= 2³⁰₆₀
= 2¹₂ h

Distance that Barbara cycled more than Ivory
= 2¹₂ x 6
= 15 km

However, since Ivory left 30 minutes earlier than Barbara and Barbara caught up with Ivory, it means that Ivory has cycled 15 km in 30 min.

1 h = 60 min 
30 min = 30 ÷ 60 = ¹₂ h

Ivory's cycling speed
= 15 ÷ ¹₂
= 15 x ²₁
= 30 km/h

(b)
Barbara's cycling speed
= 30 + 6
= 36 km/h

Answer(s): (a) 30 km/h ; (b) 36 km/h