Shiyun and Emily started off at the same spot and ran at average speeds round a 3-km circular path. Shiyun took 24 minutes to complete each round. Emily completed each round in 25 minutes.
- How far ahead of Emily would Shiyun be after 2 minute? Express your answer in metres.
- How long would it take Shiyun to meet Emily for the first time?
- How many rounds would Shiyun have completed by then?
(a)
Shiyun's speed =
324 =
18 km/min
Emily's speed =
325 km/min
Difference in speeds
=
18 -
325=
25200 -
24200=
1200 km/min
Distance between Shiyun and Emily after 2 min
= 2 x
1200=
2200 km
1 km = 1000 m
2200 km =
2200 x 1000 = 10
(b)
LCM of 24 and 25 = 600
60 min = 1 h
600 min = 600 ÷ 60 = 10
Shiyun and Emily will meet for the first time after 10 h.
(c)
Rounds Shiyun completed
= 600 ÷ 24
= 25
Answer(s): (a) 10 m; (b) 10 h; (c) 25