At 7.00 p.m., a purple car and a green car left the office and travelled at average speeds in opposite directions round a 35-km route. The purple car took 20 minutes to complete each round while the green car took 25 minutes.
- Find the speed of the purple car.
- Find the speed of the green 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 purple car
= 35 ÷
13= 35 x
31= 105 km/h
(b)
Speed of the green car
= 35 ÷
512= 35 x
125= 84 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 7 p.m. = 8.40 p.m.
Time that the two cars would meet again at the office = 8.40 p.m.
Answer(s): (a) 105 km/h; (b) 84 km/h; (c) 8.40 p.m.