At 09 20, Min left Town C and cycled towards Town D. Risa left Town C and cycled towards Town D at 09 35. Risa's cycling speed was 4 km/h faster than Min. At 11 20, Risa caught up with Min. Find the cycling speed of each cyclist.
- Min
- Risa
(a)
Duration that Risa cycled from 09 35 to 11 20
= 1
4560 = 1
34 h
Distance that Risa cycled more than Min
= 1
34 x 4
= 7 km
However, since Min left 15 minutes earlier than Risa and Risa caught up with Min, it means that Min has cycled 7 km in 15 min.
1 h = 60 min
15 min = 15 ÷ 60 =
14 h
Min's cycling speed
= 7 ÷
14 = 7 x
41 = 28 km/h
(b)
Risa's cycling speed
= 28 + 4
= 32 km/h
Answer(s): (a) 28 km/h ; (b) 32 km/h
