Esther and Luis started running together along a cross country track. When Luis completed the track in 39 minutes, Esther had run only
13 of the track. Esther’s average speed was 104 m/min slower than Luis’s.
- How long was the cross country track in m?
- Find Esther’s average speed in m/min.
(a)
When Luis completed the track:
Luis's distance = 3 u
Esther's distance = 1 u
Extra distance covered by Luis
= 3 u - 1 u
= 2 u
2 u = 104 x 39
2 u = 4056
1 u = 4056 ÷ 2 = 2028
Distance of the cross country track
= 3 u
= 3 x 2028
= 6084 m
(b)
Luis's speed
= 6084 ÷ 39
= 156 m/min
Esther's speed
= 156 - 104
= 52 m/min
Answer(s): (a) 6084 m; (b) 52 m/min