Lucy and Justin started off from the same place and drove at uniform speeds in the same direction round a 55 km circular racing track. Lucy completed each round in 50 minutes. Justin took 60 minutes to complete each round.
- How far would Justin be behind Lucy after 1 hour?
- How long after they started would it take Lucy to meet Justin for the first time? Express your answer as a whole or mixed number in h.
(a)
60 min = 1 h
1 min =
160 h
50 min =
5060 h =
56 h
60 min =
6060 h = 1 h
Lucy's speed
= 55 ÷
56= 55 x
65= 66 km/h
Justin's speed
= 55 ÷ 1
= 55 x
11= 55 km/h
Distance between Lucy and Justin after 1 hour
= 66 - 55
= 11 km
(b)
LCM of 50 and 60 = 300
300 min =
30060 h = 5 h
Time needed for Lucy to meet Justin for the first time = 5 h
Answer(s): (a) 11 km; (b) 5 h