Vanessa and David started running together along a cross country track. When David completed the track in 40 minutes, Vanessa had run only
58 of the track. Vanessa’s average speed was 96 m/min slower than David’s.
- How long was the cross country track in m?
- Find Vanessa’s average speed in m/min.
(a)
When David completed the track:
David's distance = 8 u
Vanessa's distance = 5 u
Extra distance covered by David
= 8 u - 5 u
= 3 u
3 u = 96 x 40
3 u = 3840
1 u = 3840 ÷ 3 = 1280
Distance of the cross country track
= 8 u
= 8 x 1280
= 10240 m
(b)
David's speed
= 10240 ÷ 40
= 256 m/min
Vanessa's speed
= 256 - 96
= 160 m/min
Answer(s): (a) 10240 m; (b) 160 m/min