At 4.00 p.m., a yellow car and a red car left the office and travelled at average speeds in opposite directions round a 40-km route. The yellow car took 20 minutes to complete each round while the red car took 25 minutes.
- Find the speed of the yellow car.
- Find the speed of the red car.
- If the 2 cars travelled without any interval of rest, at what time would the 2 cars next meet again at the office?
(a)
60 min = 1 h
20 min =
2060 =
13 h
25 min =
2560 =
512 h
Speed of the yellow car
= 40 ÷
13= 40 x
31= 120 km/h
(b)
Speed of the red car
= 40 ÷
512= 40 x
125= 96 km/h
(c)
LCM of 20 and 25 = 100
1 hr = 60 min
100 min = 1 h 40 min
1 h and 40 min after 4 p.m. = 5.40 p.m.
Time that the two cars would meet again at the office = 5.40 p.m.
Answer(s): (a) 120 km/h; (b) 96 km/h; (c) 5.40 p.m.