Sarah and Andy started running together along a cross country track. When Andy completed the track in 49 minutes, Sarah had run only
13 of the track. Sarah’s average speed was 110 m/min slower than Andy’s.
- How long was the cross country track in m?
- Find Sarah’s average speed in m/min.
(a)
When Andy completed the track:
Andy's distance = 3 u
Sarah's distance = 1 u
Extra distance covered by Andy
= 3 u - 1 u
= 2 u
2 u = 110 x 49
2 u = 5390
1 u = 5390 ÷ 2 = 2695
Distance of the cross country track
= 3 u
= 3 x 2695
= 8085 m
(b)
Andy's speed
= 8085 ÷ 49
= 165 m/min
Sarah's speed
= 165 - 110
= 55 m/min
Answer(s): (a) 8085 m; (b) 55 m/min