8*60=480km/h 9*60=540km/h
设原路长为x
x/480=(x+3)/540-1/8*60
x/480*4320=(x+3)/540*4320-4320*15/2
540x=480x+1440-576
60x=864
x=14.4
原路长14.4km
8*60=480km/h 9*60=540km/h
设原路长为x
x/480=(x+3)/540-1/8*60
x/480*4320=(x+3)/540*4320-4320*15/2
540x=480x+1440-576
60x=864
x=14.4
原路长14.4km