Xuan and Rachel started off at the same spot and ran at average speeds round a 4-km circular path. Xuan took 12 minutes to complete each round. Rachel completed each round in 25 minutes.
- How far ahead of Rachel would Xuan be after 6 minute? Express your answer in metres.
- How long would it take Xuan to meet Rachel for the first time?
- How many rounds would Xuan have completed by then?
(a)
Xuan's speed =
412 =
13 km/min
Rachel's speed =
425 km/min
Difference in speeds
=
13 -
425=
2575 -
1275=
1375 km/min
Distance between Xuan and Rachel after 6 min
= 6 x
1375= 1
375 km
1 km = 1000 m
1
375 km = 1
375 x 1000 = 1040
(b)
LCM of 12 and 25 = 300
60 min = 1 h
300 min = 300 ÷ 60 = 5
Xuan and Rachel will meet for the first time after 5 h.
(c)
Rounds Xuan completed
= 300 ÷ 12
= 25
Answer(s): (a) 1040 m; (b) 5 h; (c) 25