Kylie and Lee started running together along a cross country track. When Lee completed the track in 40 minutes, Kylie had run only
13 of the track. Kylie’s average speed was 100 m/min slower than Lee’s.
- How long was the cross country track in m?
- Find Kylie’s average speed in m/min.
(a)
When Lee completed the track:
Lee's distance = 3 u
Kylie's distance = 1 u
Extra distance covered by Lee
= 3 u - 1 u
= 2 u
2 u = 100 x 40
2 u = 4000
1 u = 4000 ÷ 2 = 2000
Distance of the cross country track
= 3 u
= 3 x 2000
= 6000 m
(b)
Lee's speed
= 6000 ÷ 40
= 150 m/min
Kylie's speed
= 150 - 100
= 50 m/min
Answer(s): (a) 6000 m; (b) 50 m/min