Jen and Xandra started off at the same spot and ran at average speeds round a 5-km circular path. Jen took 20 minutes to complete each round. Xandra completed each round in 24 minutes.
- How far ahead of Xandra would Jen be after 9 minute? Express your answer in metres.
- How long would it take Jen to meet Xandra for the first time?
- How many rounds would Jen have completed by then?
(a)
Jen's speed =
520 =
14 km/min
Xandra's speed =
524 km/min
Difference in speeds
=
14 -
524=
624 -
524=
124 km/min
Distance between Jen and Xandra after 9 min
= 9 x
124=
924 km
1 km = 1000 m
924 km =
924 x 1000 = 375
(b)
LCM of 20 and 24 = 120
60 min = 1 h
120 min = 120 ÷ 60 = 2
Jen and Xandra will meet for the first time after 2 h.
(c)
Rounds Jen completed
= 120 ÷ 20
= 6
Answer(s): (a) 375 m; (b) 2 h; (c) 6