Gem and Bobby started off from the same place and drove at uniform speeds in the same direction round a 30 km circular racing track. Gem completed each round in 40 minutes. Bobby took 100 minutes to complete each round.
- How far would Bobby be behind Gem after 1 hour?
- How long after they started would it take Gem to meet Bobby 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
100 min =
10060 h = 1
23 h
Gem's speed
= 30 ÷
23= 30 x
32= 45 km/h
Bobby's speed
= 30 ÷ 1
23= 30 x
35= 18 km/h
Distance between Gem and Bobby after 1 hour
= 45 - 18
= 27 km
(b)
LCM of 40 and 100 = 200
200 min =
20060 h = 3
13 h
Time needed for Gem to meet Bobby for the first time = 3
13 h
Answer(s): (a) 27 km; (b) 3
13 h