Emily and Jeremy started running together along a cross country track. When Jeremy completed the track in 50 minutes, Emily had run only
47 of the track. Emily’s average speed was 108 m/min slower than Jeremy’s.
- How long was the cross country track in m?
- Find Emily’s average speed in m/min.
(a)
When Jeremy completed the track:
Jeremy's distance = 7 u
Emily's distance = 4 u
Extra distance covered by Jeremy
= 7 u - 4 u
= 3 u
3 u = 108 x 50
3 u = 5400
1 u = 5400 ÷ 3 = 1800
Distance of the cross country track
= 7 u
= 7 x 1800
= 12600 m
(b)
Jeremy's speed
= 12600 ÷ 50
= 252 m/min
Emily's speed
= 252 - 108
= 144 m/min
Answer(s): (a) 12600 m; (b) 144 m/min