At 06 20, Opal left Town X and cycled towards Town Y. Kathy left Town X and cycled towards Town Y at 06 50. Kathy's cycling speed was 2 km/h faster than Opal. At 11 20, Kathy caught up with Opal. Find the cycling speed of each cyclist.
- Opal
- Kathy
(a)
Duration that Kathy cycled from 06 50 to 11 20
= 4
3060 = 4
12 h
Distance that Kathy cycled more than Opal
= 4
12 x 2
= 9 km
However, since Opal left 30 minutes earlier than Kathy and Kathy caught up with Opal, it means that Opal has cycled 9 km in 30 min.
1 h = 60 min
30 min = 30 ÷ 60 =
12 h
Opal's cycling speed
= 9 ÷
12 = 9 x
21 = 18 km/h
(b)
Kathy's cycling speed
= 18 + 2
= 20 km/h
Answer(s): (a) 18 km/h ; (b) 20 km/h
