Tina and Archie started off from the same place and drove at uniform speeds in the same direction round a 60 km circular racing track. Tina completed each round in 60 minutes. Archie took 90 minutes to complete each round.
- How far would Archie be behind Tina after 1 hour?
- How long after they started would it take Tina to meet Archie for the first time? Express your answer as a whole or mixed number in h.
(a)
60 min = 1 h
1 min =
160 h
60 min =
6060 h = 1 h
90 min =
9060 h = 1
12 h
Tina's speed
= 60 ÷ 1
= 60 x
11= 60 km/h
Archie's speed
= 60 ÷ 1
12= 60 x
23= 40 km/h
Distance between Tina and Archie after 1 hour
= 60 - 40
= 20 km
(b)
LCM of 60 and 90 = 180
180 min =
18060 h = 3 h
Time needed for Tina to meet Archie for the first time = 3 h
Answer(s): (a) 20 km; (b) 3 h