Shiyun and Mark started running together along a cross country track. When Mark completed the track in 40 minutes, Shiyun had run only
35 of the track. Shiyun’s average speed was 98 m/min slower than Mark’s.
- How long was the cross country track in m?
- Find Shiyun’s average speed in m/min.
(a)
When Mark completed the track:
Mark's distance = 5 u
Shiyun's distance = 3 u
Extra distance covered by Mark
= 5 u - 3 u
= 2 u
2 u = 98 x 40
2 u = 3920
1 u = 3920 ÷ 2 = 1960
Distance of the cross country track
= 5 u
= 5 x 1960
= 9800 m
(b)
Mark's speed
= 9800 ÷ 40
= 245 m/min
Shiyun's speed
= 245 - 98
= 147 m/min
Answer(s): (a) 9800 m; (b) 147 m/min