Emily and Diana started off at the same spot and ran at average speeds round a 2-km circular path. Emily took 12 minutes to complete each round. Diana completed each round in 25 minutes.
- How far ahead of Diana would Emily be after 3 minute? Express your answer in metres.
- How long would it take Emily to meet Diana for the first time?
- How many rounds would Emily have completed by then?
(a)
Emily's speed =
212 =
16 km/min
Diana's speed =
225 km/min
Difference in speeds
=
16 -
225=
25150 -
12150=
13150 km/min
Distance between Emily and Diana after 3 min
= 3 x
13150=
39150 km
1 km = 1000 m
39150 km =
39150 x 1000 = 260
(b)
LCM of 12 and 25 = 300
60 min = 1 h
300 min = 300 ÷ 60 = 5
Emily and Diana will meet for the first time after 5 h.
(c)
Rounds Emily completed
= 300 ÷ 12
= 25
Answer(s): (a) 260 m; (b) 5 h; (c) 25