Anna and Billy started running together along a cross country track. When Billy completed the track in 30 minutes, Anna had run only
13 of the track. Anna’s average speed was 112 m/min slower than Billy’s.
- How long was the cross country track in m?
- Find Anna’s average speed in m/min.
(a)
When Billy completed the track:
Billy's distance = 3 u
Anna's distance = 1 u
Extra distance covered by Billy
= 3 u - 1 u
= 2 u
2 u = 112 x 30
2 u = 3360
1 u = 3360 ÷ 2 = 1680
Distance of the cross country track
= 3 u
= 3 x 1680
= 5040 m
(b)
Billy's speed
= 5040 ÷ 30
= 168 m/min
Anna's speed
= 168 - 112
= 56 m/min
Answer(s): (a) 5040 m; (b) 56 m/min