At 07 10, Diana left Town X and cycled towards Town Y. Sarah left Town X and cycled towards Town Y at 07 40. Sarah's cycling speed was 4 km/h faster than Diana. At 12 10, Sarah caught up with Diana. Find the cycling speed of each cyclist.
- Diana
- Sarah
(a)
Duration that Sarah cycled from 07 40 to 12 10
= 4
3060 = 4
12 h
Distance that Sarah cycled more than Diana
= 4
12 x 4
= 18 km
However, since Diana left 30 minutes earlier than Sarah and Sarah caught up with Diana, it means that Diana has cycled 18 km in 30 min.
1 h = 60 min
30 min = 30 ÷ 60 =
12 h
Diana's cycling speed
= 18 ÷
12 = 18 x
21 = 36 km/h
(b)
Sarah's cycling speed
= 36 + 4
= 40 km/h
Answer(s): (a) 36 km/h ; (b) 40 km/h
