Sarah and Bobby started running together along a cross country track. When Bobby completed the track in 33 minutes, Sarah had run only
35 of the track. Sarah’s average speed was 104 m/min slower than Bobby’s.
- How long was the cross country track in m?
- Find Sarah’s average speed in m/min.
(a)
When Bobby completed the track:
Bobby's distance = 5 u
Sarah's distance = 3 u
Extra distance covered by Bobby
= 5 u - 3 u
= 2 u
2 u = 104 x 33
2 u = 3432
1 u = 3432 ÷ 2 = 1716
Distance of the cross country track
= 5 u
= 5 x 1716
= 8580 m
(b)
Bobby's speed
= 8580 ÷ 33
= 260 m/min
Sarah's speed
= 260 - 104
= 156 m/min
Answer(s): (a) 8580 m; (b) 156 m/min