Natalie and Mark started running together along a cross country track. When Mark completed the track in 46 minutes, Natalie had run only
35 of the track. Natalie’s average speed was 100 m/min slower than Mark’s.
- How long was the cross country track in m?
- Find Natalie’s average speed in m/min.
(a)
When Mark completed the track:
Mark's distance = 5 u
Natalie's distance = 3 u
Extra distance covered by Mark
= 5 u - 3 u
= 2 u
2 u = 100 x 46
2 u = 4600
1 u = 4600 ÷ 2 = 2300
Distance of the cross country track
= 5 u
= 5 x 2300
= 11500 m
(b)
Mark's speed
= 11500 ÷ 46
= 250 m/min
Natalie's speed
= 250 - 100
= 150 m/min
Answer(s): (a) 11500 m; (b) 150 m/min