Irene and Seth started running together along a cross country track. When Seth completed the track in 49 minutes, Irene had run only
47 of the track. Irene’s average speed was 108 m/min slower than Seth’s.
- How long was the cross country track in m?
- Find Irene’s average speed in m/min.
(a)
When Seth completed the track:
Seth's distance = 7 u
Irene's distance = 4 u
Extra distance covered by Seth
= 7 u - 4 u
= 3 u
3 u = 108 x 49
3 u = 5292
1 u = 5292 ÷ 3 = 1764
Distance of the cross country track
= 7 u
= 7 x 1764
= 12348 m
(b)
Seth's speed
= 12348 ÷ 49
= 252 m/min
Irene's speed
= 252 - 108
= 144 m/min
Answer(s): (a) 12348 m; (b) 144 m/min