Opal and Ryan started off from the same place and drove at uniform speeds in the same direction round a 60 km circular racing track. Opal completed each round in 40 minutes. Ryan took 90 minutes to complete each round.
- How far would Ryan be behind Opal after 1 hour?
- How long after they started would it take Opal to meet Ryan for the first time? Express your answer as a whole or mixed number in h.
(a)
60 min = 1 h
1 min =
160 h
40 min =
4060 h =
23 h
90 min =
9060 h = 1
12 h
Opal's speed
= 60 ÷
23= 60 x
32= 90 km/h
Ryan's speed
= 60 ÷ 1
12= 60 x
23= 40 km/h
Distance between Opal and Ryan after 1 hour
= 90 - 40
= 50 km
(b)
LCM of 40 and 90 = 360
360 min =
36060 h = 6 h
Time needed for Opal to meet Ryan for the first time = 6 h
Answer(s): (a) 50 km; (b) 6 h