Natalie and Oscar started running together along a cross country track. When Oscar completed the track in 21 minutes, Natalie had run only
38 of the track. Natalie’s average speed was 100 m/min slower than Oscar’s.
- How long was the cross country track in m?
- Find Natalie’s average speed in m/min.
(a)
When Oscar completed the track:
Oscar's distance = 8 u
Natalie's distance = 3 u
Extra distance covered by Oscar
= 8 u - 3 u
= 5 u
5 u = 100 x 21
5 u = 2100
1 u = 2100 ÷ 5 = 420
Distance of the cross country track
= 8 u
= 8 x 420
= 3360 m
(b)
Oscar's speed
= 3360 ÷ 21
= 160 m/min
Natalie's speed
= 160 - 100
= 60 m/min
Answer(s): (a) 3360 m; (b) 60 m/min