Kathy and Sam started running together along a cross country track. When Sam completed the track in 30 minutes, Kathy had run only
49 of the track. Kathy’s average speed was 115 m/min slower than Sam’s.
- How long was the cross country track in m?
- Find Kathy’s average speed in m/min.
(a)
When Sam completed the track:
Sam's distance = 9 u
Kathy's distance = 4 u
Extra distance covered by Sam
= 9 u - 4 u
= 5 u
5 u = 115 x 30
5 u = 3450
1 u = 3450 ÷ 5 = 690
Distance of the cross country track
= 9 u
= 9 x 690
= 6210 m
(b)
Sam's speed
= 6210 ÷ 30
= 207 m/min
Kathy's speed
= 207 - 115
= 92 m/min
Answer(s): (a) 6210 m; (b) 92 m/min