Erika and Marion started off at the same spot and ran at average speeds round a 2-km circular path. Erika took 24 minutes to complete each round. Marion completed each round in 30 minutes.
- How far ahead of Marion would Erika be after 9 minute? Express your answer in metres.
- How long would it take Erika to meet Marion for the first time?
- How many rounds would Erika have completed by then?
(a)
Erika's speed =
224 =
112 km/min
Marion's speed =
115 km/min
Difference in speeds
=
112 -
115=
560 -
460=
160 km/min
Distance between Erika and Marion after 9 min
= 9 x
160=
960 km
1 km = 1000 m
960 km =
960 x 1000 = 150
(b)
LCM of 24 and 30 = 120
60 min = 1 h
120 min = 120 ÷ 60 = 2
Erika and Marion will meet for the first time after 2 h.
(c)
Rounds Erika completed
= 120 ÷ 24
= 5
Answer(s): (a) 150 m; (b) 2 h; (c) 5