Vanessa and Sean started off from the same place and drove at uniform speeds in the same direction round a 45 km circular racing track. Vanessa completed each round in 60 minutes. Sean took 90 minutes to complete each round.
- How far would Sean be behind Vanessa after 1 hour?
- How long after they started would it take Vanessa to meet Sean 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
Vanessa's speed
= 45 ÷ 1
= 45 x
11= 45 km/h
Sean's speed
= 45 ÷ 1
12= 45 x
23= 30 km/h
Distance between Vanessa and Sean after 1 hour
= 45 - 30
= 15 km
(b)
LCM of 60 and 90 = 180
180 min =
18060 h = 3 h
Time needed for Vanessa to meet Sean for the first time = 3 h
Answer(s): (a) 15 km; (b) 3 h