Natalie and Perry started running together along a cross country track. When Perry completed the track in 21 minutes, Natalie had run only
13 of the track. Natalie’s average speed was 110 m/min slower than Perry’s.
- How long was the cross country track in m?
- Find Natalie’s average speed in m/min.
(a)
When Perry completed the track:
Perry's distance = 3 u
Natalie's distance = 1 u
Extra distance covered by Perry
= 3 u - 1 u
= 2 u
2 u = 110 x 21
2 u = 2310
1 u = 2310 ÷ 2 = 1155
Distance of the cross country track
= 3 u
= 3 x 1155
= 3465 m
(b)
Perry's speed
= 3465 ÷ 21
= 165 m/min
Natalie's speed
= 165 - 110
= 55 m/min
Answer(s): (a) 3465 m; (b) 55 m/min