SOLUTION: The speed of a freight train is 20 miles per hour slower than the speed of a passenger train. The freight train travels 390 miles in the same time that it takes the passenger train

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Question 278897: The speed of a freight train is 20 miles per hour slower than the speed of a passenger train. The freight train travels 390 miles in the same time that it takes the passenger train to travel 480 miles. find the speed of the freight train.
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
D=RT
390=(R-20)T
T=390/(R-20)
480=RT
T=480/R
SET THE 2 EQUATION EQUAL.
390/(R-20)=480/R CROSSS MULTIPLY
480(R-20)=390R
480R-9,600=390R
480R-390R=9,600
90R=9,600
R=9,600/90
R=106.67 MPH. FOR THE PASSENGER TRAIN.
106.67-20=87.76 MPH. FOR THE FREIGHT TRAIN.