Opal and Henry started running together along a cross country track. When Henry completed the track in 20 minutes, Opal had run only
59 of the track. Opal’s average speed was 108 m/min slower than Henry’s.
- How long was the cross country track in m?
- Find Opal’s average speed in m/min.
(a)
When Henry completed the track:
Henry's distance = 9 u
Opal's distance = 5 u
Extra distance covered by Henry
= 9 u - 5 u
= 4 u
4 u = 108 x 20
4 u = 2160
1 u = 2160 ÷ 4 = 540
Distance of the cross country track
= 9 u
= 9 x 540
= 4860 m
(b)
Henry's speed
= 4860 ÷ 20
= 243 m/min
Opal's speed
= 243 - 108
= 135 m/min
Answer(s): (a) 4860 m; (b) 135 m/min