At 09 15, Mary left Town G and cycled towards Town H. Gwen left Town G and cycled towards Town H at 09 45. Gwen's cycling speed was 4 km/h faster than Mary. At 11 15, Gwen caught up with Mary. Find the cycling speed of each cyclist.
- Mary
- Gwen
(a)
Duration that Gwen cycled from 09 45 to 11 15
= 1
3060 = 1
12 h
Distance that Gwen cycled more than Mary
= 1
12 x 4
= 6 km
However, since Mary left 30 minutes earlier than Gwen and Gwen caught up with Mary, it means that Mary has cycled 6 km in 30 min.
1 h = 60 min
30 min = 30 ÷ 60 =
12 h
Mary's cycling speed
= 6 ÷
12 = 6 x
21 = 12 km/h
(b)
Gwen's cycling speed
= 12 + 4
= 16 km/h
Answer(s): (a) 12 km/h ; (b) 16 km/h
