Gem and Harry 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 50 minutes. Harry took 90 minutes to complete each round.
- How far would Harry be behind Gem after 1 hour?
- How long after they started would it take Gem to meet Harry 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
90 min =
9060 h = 1
12 h
Gem's speed
= 30 ÷
56= 30 x
65= 36 km/h
Harry's speed
= 30 ÷ 1
12= 30 x
23= 20 km/h
Distance between Gem and Harry after 1 hour
= 36 - 20
= 16 km
(b)
LCM of 50 and 90 = 450
450 min =
45060 h = 7
12 h
Time needed for Gem to meet Harry for the first time = 7
12 h
Answer(s): (a) 16 km; (b) 7
12 h