Irene and Eric started running together along a cross country track. When Eric completed the track in 40 minutes, Irene had run only
13 of the track. Irene’s average speed was 108 m/min slower than Eric’s.
- How long was the cross country track in m?
- Find Irene’s average speed in m/min.
(a)
When Eric completed the track:
Eric's distance = 3 u
Irene's distance = 1 u
Extra distance covered by Eric
= 3 u - 1 u
= 2 u
2 u = 108 x 40
2 u = 4320
1 u = 4320 ÷ 2 = 2160
Distance of the cross country track
= 3 u
= 3 x 2160
= 6480 m
(b)
Eric's speed
= 6480 ÷ 40
= 162 m/min
Irene's speed
= 162 - 108
= 54 m/min
Answer(s): (a) 6480 m; (b) 54 m/min