Irene and Fanny started off at the same spot and ran at average speeds round a 3-km circular path. Irene took 24 minutes to complete each round. Fanny completed each round in 25 minutes.
- How far ahead of Fanny would Irene be after 1 minute? Express your answer in metres.
- How long would it take Irene to meet Fanny for the first time?
- How many rounds would Irene have completed by then?
(a)
Irene's speed =
324 =
18 km/min
Fanny's speed =
325 km/min
Difference in speeds
=
18 -
325=
25200 -
24200=
1200 km/min
Distance between Irene and Fanny after 1 min
= 1 x
1200=
1200 km
1 km = 1000 m
1200 km =
1200 x 1000 = 5
(b)
LCM of 24 and 25 = 600
60 min = 1 h
600 min = 600 ÷ 60 = 10
Irene and Fanny will meet for the first time after 10 h.
(c)
Rounds Irene completed
= 600 ÷ 24
= 25
Answer(s): (a) 5 m; (b) 10 h; (c) 25