Mary and Fabian started running together along a cross country track. When Fabian completed the track in 31 minutes, Mary had run only
13 of the track. Mary’s average speed was 104 m/min slower than Fabian’s.
- How long was the cross country track in m?
- Find Mary’s average speed in m/min.
(a)
When Fabian completed the track:
Fabian's distance = 3 u
Mary's distance = 1 u
Extra distance covered by Fabian
= 3 u - 1 u
= 2 u
2 u = 104 x 31
2 u = 3224
1 u = 3224 ÷ 2 = 1612
Distance of the cross country track
= 3 u
= 3 x 1612
= 4836 m
(b)
Fabian's speed
= 4836 ÷ 31
= 156 m/min
Mary's speed
= 156 - 104
= 52 m/min
Answer(s): (a) 4836 m; (b) 52 m/min