Emma and Carl started running together along a cross country track. When Carl completed the track in 30 minutes, Emma had run only
13 of the track. Emma’s average speed was 100 m/min slower than Carl’s.
- How long was the cross country track in m?
- Find Emma’s average speed in m/min.
(a)
When Carl completed the track:
Carl's distance = 3 u
Emma's distance = 1 u
Extra distance covered by Carl
= 3 u - 1 u
= 2 u
2 u = 100 x 30
2 u = 3000
1 u = 3000 ÷ 2 = 1500
Distance of the cross country track
= 3 u
= 3 x 1500
= 4500 m
(b)
Carl's speed
= 4500 ÷ 30
= 150 m/min
Emma's speed
= 150 - 100
= 50 m/min
Answer(s): (a) 4500 m; (b) 50 m/min