Zara and Jen started off at the same spot and ran at average speeds round a 2-km circular path. Zara took 16 minutes to complete each round. Jen completed each round in 30 minutes.
- How far ahead of Jen would Zara be after 3 minute? Express your answer in metres.
- How long would it take Zara to meet Jen for the first time?
- How many rounds would Zara have completed by then?
(a)
Zara's speed =
216 =
18 km/min
Jen's speed =
115 km/min
Difference in speeds
=
18 -
115=
15120 -
8120=
7120 km/min
Distance between Zara and Jen after 3 min
= 3 x
7120=
21120 km
1 km = 1000 m
21120 km =
21120 x 1000 = 175
(b)
LCM of 16 and 30 = 240
60 min = 1 h
240 min = 240 ÷ 60 = 4
Zara and Jen will meet for the first time after 4 h.
(c)
Rounds Zara completed
= 240 ÷ 16
= 15
Answer(s): (a) 175 m; (b) 4 h; (c) 15