Rachel and Pierre started off from the same place and drove at uniform speeds in the same direction round a 30 km circular racing track. Rachel completed each round in 40 minutes. Pierre took 50 minutes to complete each round.
- How far would Pierre be behind Rachel after 1 hour?
- How long after they started would it take Rachel to meet Pierre 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
50 min =
5060 h =
56 h
Rachel's speed
= 30 ÷
23= 30 x
32= 45 km/h
Pierre's speed
= 30 ÷
56= 30 x
65= 36 km/h
Distance between Rachel and Pierre after 1 hour
= 45 - 36
= 9 km
(b)
LCM of 40 and 50 = 200
200 min =
20060 h = 3
13 h
Time needed for Rachel to meet Pierre for the first time = 3
13 h
Answer(s): (a) 9 km; (b) 3
13 h