Jean and Sam started off from the same place and drove at uniform speeds in the same direction round a 60 km circular racing track. Jean completed each round in 50 minutes. Sam took 60 minutes to complete each round.
- How far would Sam be behind Jean after 1 hour?
- How long after they started would it take Jean to meet Sam 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
Jean's speed
= 60 ÷
56= 60 x
65= 72 km/h
Sam's speed
= 60 ÷ 1
= 60 x
11= 60 km/h
Distance between Jean and Sam after 1 hour
= 72 - 60
= 12 km
(b)
LCM of 50 and 60 = 300
300 min =
30060 h = 5 h
Time needed for Jean to meet Sam for the first time = 5 h
Answer(s): (a) 12 km; (b) 5 h