At 05 20, Risa left Town H and cycled towards Town J. Erika left Town H and cycled towards Town J at 05 50. Erika's cycling speed was 2 km/h faster than Risa. At 13 20, Erika caught up with Risa. Find the cycling speed of each cyclist.
- Risa
- Erika
(a)
Duration that Erika cycled from 05 50 to 13 20
= 7
3060 = 7
12 h
Distance that Erika cycled more than Risa
= 7
12 x 2
= 15 km
However, since Risa left 30 minutes earlier than Erika and Erika caught up with Risa, it means that Risa has cycled 15 km in 30 min.
1 h = 60 min
30 min = 30 ÷ 60 =
12 h
Risa's cycling speed
= 15 ÷
12 = 15 x
21 = 30 km/h
(b)
Erika's cycling speed
= 30 + 2
= 32 km/h
Answer(s): (a) 30 km/h ; (b) 32 km/h
