Gillian and Betty started off at the same spot and ran at average speeds round a 2-km circular path. Gillian took 24 minutes to complete each round. Betty completed each round in 30 minutes.
- How far ahead of Betty would Gillian be after 6 minute? Express your answer in metres.
- How long would it take Gillian to meet Betty for the first time?
- How many rounds would Gillian have completed by then?
(a)
Gillian's speed =
224 =
112 km/min
Betty's speed =
115 km/min
Difference in speeds
=
112 -
115=
560 -
460=
160 km/min
Distance between Gillian and Betty after 6 min
= 6 x
160=
660 km
1 km = 1000 m
660 km =
660 x 1000 = 100
(b)
LCM of 24 and 30 = 120
60 min = 1 h
120 min = 120 ÷ 60 = 2
Gillian and Betty will meet for the first time after 2 h.
(c)
Rounds Gillian completed
= 120 ÷ 24
= 5
Answer(s): (a) 100 m; (b) 2 h; (c) 5