Xuan and Zeph started off from the same place and drove at uniform speeds in the same direction round a 50 km circular racing track. Xuan completed each round in 50 minutes. Zeph took 60 minutes to complete each round.
- How far would Zeph be behind Xuan after 1 hour?
- How long after they started would it take Xuan to meet Zeph 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
60 min =
6060 h = 1 h
Xuan's speed
= 50 ÷
56= 50 x
65= 60 km/h
Zeph's speed
= 50 ÷ 1
= 50 x
11= 50 km/h
Distance between Xuan and Zeph after 1 hour
= 60 - 50
= 10 km
(b)
LCM of 50 and 60 = 300
300 min =
30060 h = 5 h
Time needed for Xuan to meet Zeph for the first time = 5 h
Answer(s): (a) 10 km; (b) 5 h