Sarah and Pierre started running together along a cross country track. When Pierre completed the track in 37 minutes, Sarah had run only
47 of the track. Sarah’s average speed was 108 m/min slower than Pierre’s.
- How long was the cross country track in m?
- Find Sarah’s average speed in m/min.
(a)
When Pierre completed the track:
Pierre's distance = 7 u
Sarah's distance = 4 u
Extra distance covered by Pierre
= 7 u - 4 u
= 3 u
3 u = 108 x 37
3 u = 3996
1 u = 3996 ÷ 3 = 1332
Distance of the cross country track
= 7 u
= 7 x 1332
= 9324 m
(b)
Pierre's speed
= 9324 ÷ 37
= 252 m/min
Sarah's speed
= 252 - 108
= 144 m/min
Answer(s): (a) 9324 m; (b) 144 m/min