At 07 15, Betty left Town P and cycled towards Town Q. Vanessa left Town P and cycled towards Town Q at 07 45. Vanessa's cycling speed was 4 km/h faster than Betty. At 12 15, Vanessa caught up with Betty. Find the cycling speed of each cyclist.

1. Betty
2. Vanessa

(a)
Duration that Vanessa cycled from 07 45 to 12 15
= 4³⁰₆₀
= 4¹₂ h

Distance that Vanessa cycled more than Betty
= 4¹₂ x 4
= 18 km

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

1 h = 60 min 
30 min = 30 ÷ 60 = ¹₂ h

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

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

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