Betty and Zeph started running together along a cross country track. When Zeph completed the track in 35 minutes, Betty had run only
49 of the track. Betty’s average speed was 105 m/min slower than Zeph’s.
- How long was the cross country track in m?
- Find Betty’s average speed in m/min.
(a)
When Zeph completed the track:
Zeph's distance = 9 u
Betty's distance = 4 u
Extra distance covered by Zeph
= 9 u - 4 u
= 5 u
5 u = 105 x 35
5 u = 3675
1 u = 3675 ÷ 5 = 735
Distance of the cross country track
= 9 u
= 9 x 735
= 6615 m
(b)
Zeph's speed
= 6615 ÷ 35
= 189 m/min
Betty's speed
= 189 - 105
= 84 m/min
Answer(s): (a) 6615 m; (b) 84 m/min