Opal and Liam started running together along a cross country track. When Liam completed the track in 21 minutes, Opal had run only
35 of the track. Opal’s average speed was 104 m/min slower than Liam’s.
- How long was the cross country track in m?
- Find Opal’s average speed in m/min.
(a)
When Liam completed the track:
Liam's distance = 5 u
Opal's distance = 3 u
Extra distance covered by Liam
= 5 u - 3 u
= 2 u
2 u = 104 x 21
2 u = 2184
1 u = 2184 ÷ 2 = 1092
Distance of the cross country track
= 5 u
= 5 x 1092
= 5460 m
(b)
Liam's speed
= 5460 ÷ 21
= 260 m/min
Opal's speed
= 260 - 104
= 156 m/min
Answer(s): (a) 5460 m; (b) 156 m/min