Opal and Harry started running together along a cross country track. When Harry completed the track in 20 minutes, Opal had run only
37 of the track. Opal’s average speed was 108 m/min slower than Harry’s.
- How long was the cross country track in m?
- Find Opal’s average speed in m/min.
(a)
When Harry completed the track:
Harry's distance = 7 u
Opal's distance = 3 u
Extra distance covered by Harry
= 7 u - 3 u
= 4 u
4 u = 108 x 20
4 u = 2160
1 u = 2160 ÷ 4 = 540
Distance of the cross country track
= 7 u
= 7 x 540
= 3780 m
(b)
Harry's speed
= 3780 ÷ 20
= 189 m/min
Opal's speed
= 189 - 108
= 81 m/min
Answer(s): (a) 3780 m; (b) 81 m/min