Marion and Nora started off at the same spot and ran at average speeds round a 4-km circular path. Marion took 24 minutes to complete each round. Nora completed each round in 30 minutes.
- How far ahead of Nora would Marion be after 9 minute? Express your answer in metres.
- How long would it take Marion to meet Nora for the first time?
- How many rounds would Marion have completed by then?
(a)
Marion's speed =
424 =
16 km/min
Nora's speed =
215 km/min
Difference in speeds
=
16 -
215=
530 -
430=
130 km/min
Distance between Marion and Nora after 9 min
= 9 x
130=
930 km
1 km = 1000 m
930 km =
930 x 1000 = 300
(b)
LCM of 24 and 30 = 120
60 min = 1 h
120 min = 120 ÷ 60 = 2
Marion and Nora will meet for the first time after 2 h.
(c)
Rounds Marion completed
= 120 ÷ 24
= 5
Answer(s): (a) 300 m; (b) 2 h; (c) 5