Linda and Yoko started off at the same spot and ran at average speeds round a 3-km circular path. Linda took 15 minutes to complete each round. Yoko completed each round in 20 minutes.
- How far ahead of Yoko would Linda be after 2 minute? Express your answer in metres.
- How long would it take Linda to meet Yoko for the first time?
- How many rounds would Linda have completed by then?
(a)
Linda's speed =
315 =
15 km/min
Yoko's speed =
320 km/min
Difference in speeds
=
15 -
320=
420 -
320=
120 km/min
Distance between Linda and Yoko after 2 min
= 2 x
120=
220 km
1 km = 1000 m
220 km =
220 x 1000 = 100
(b)
LCM of 15 and 20 = 60
60 min = 1 h
60 min = 60 ÷ 60 = 1
Linda and Yoko will meet for the first time after 1 h.
(c)
Rounds Linda completed
= 60 ÷ 15
= 4
Answer(s): (a) 100 m; (b) 1 h; (c) 4