Usha and Julie started off at the same spot and ran at average speeds round a 3-km circular path. Usha took 24 minutes to complete each round. Julie completed each round in 25 minutes.
- How far ahead of Julie would Usha be after 10 minute? Express your answer in metres.
- How long would it take Usha to meet Julie for the first time?
- How many rounds would Usha have completed by then?
(a)
Usha's speed =
324 =
18 km/min
Julie's speed =
325 km/min
Difference in speeds
=
18 -
325=
25200 -
24200=
1200 km/min
Distance between Usha and Julie after 10 min
= 10 x
1200=
10200 km
1 km = 1000 m
10200 km =
10200 x 1000 = 50
(b)
LCM of 24 and 25 = 600
60 min = 1 h
600 min = 600 ÷ 60 = 10
Usha and Julie will meet for the first time after 10 h.
(c)
Rounds Usha completed
= 600 ÷ 24
= 25
Answer(s): (a) 50 m; (b) 10 h; (c) 25