Question 319878
D=RT
300=(R+18)T OR T=300/(R+18)
210=RT OR T=210/R
300/(R+18)=210/R CROSS MULTIPLY.
300R=210(R+18)
300R=210R+3,780
300R-210R=3,780
90R=3,780
R=3,780/90
R=42 MPH. FOR THE FREIGHT TRAIN
42+18=60 MPH. FOR THE PASSENGER TRAIN.
PROOF:
300/60=210/42
5=5 TIME OF THE TRIPS.