Cindy and Ben started running together along a cross country track. When Ben completed the track in 50 minutes, Cindy had run only
35 of the track. Cindy’s average speed was 100 m/min slower than Ben’s.
- How long was the cross country track in m?
- Find Cindy’s average speed in m/min.
(a)
When Ben completed the track:
Ben's distance = 5 u
Cindy's distance = 3 u
Extra distance covered by Ben
= 5 u - 3 u
= 2 u
2 u = 100 x 50
2 u = 5000
1 u = 5000 ÷ 2 = 2500
Distance of the cross country track
= 5 u
= 5 x 2500
= 12500 m
(b)
Ben's speed
= 12500 ÷ 50
= 250 m/min
Cindy's speed
= 250 - 100
= 150 m/min
Answer(s): (a) 12500 m; (b) 150 m/min