Lucy and Abi started off at the same spot and ran at average speeds round a 4-km circular path. Lucy took 16 minutes to complete each round. Abi completed each round in 30 minutes.
- How far ahead of Abi would Lucy be after 3 minute? Express your answer in metres.
- How long would it take Lucy to meet Abi for the first time?
- How many rounds would Lucy have completed by then?
(a)
Lucy's speed =
416 =
14 km/min
Abi's speed =
215 km/min
Difference in speeds
=
14 -
215=
1560 -
860=
760 km/min
Distance between Lucy and Abi after 3 min
= 3 x
760=
2160 km
1 km = 1000 m
2160 km =
2160 x 1000 = 350
(b)
LCM of 16 and 30 = 240
60 min = 1 h
240 min = 240 ÷ 60 = 4
Lucy and Abi will meet for the first time after 4 h.
(c)
Rounds Lucy completed
= 240 ÷ 16
= 15
Answer(s): (a) 350 m; (b) 4 h; (c) 15