Suppose the speed of passenger car is 4x, the speed of freight car is 5x, and the distance between the two places is y, y = 5x * 4+4.8x * 4+115; Y=[(5x*4)÷4x+4]*5x=45x, then 20x+19.2x+15 = 45x, x is about 20, y=45*20=900, so two.