Sarah and Tammy started off at the same spot and ran at average speeds round a 3-km circular path. Sarah took 12 minutes to complete each round. Tammy completed each round in 25 minutes.
- How far ahead of Tammy would Sarah be after 5 minute? Express your answer in metres.
- How long would it take Sarah to meet Tammy for the first time?
- How many rounds would Sarah have completed by then?
(a)
Sarah's speed =
312 =
14 km/min
Tammy's speed =
325 km/min
Difference in speeds
=
14 -
325=
25100 -
12100=
13100 km/min
Distance between Sarah and Tammy after 5 min
= 5 x
13100=
65100 km
1 km = 1000 m
65100 km =
65100 x 1000 = 650
(b)
LCM of 12 and 25 = 300
60 min = 1 h
300 min = 300 ÷ 60 = 5
Sarah and Tammy will meet for the first time after 5 h.
(c)
Rounds Sarah completed
= 300 ÷ 12
= 25
Answer(s): (a) 650 m; (b) 5 h; (c) 25