find the speed of each train

Question

The speed of a passenger train is 20 mph faster than the speed of a freight train. The passenger train travels 340 miles in the same time it takes the freight train to travel 240 miles. Find the speed of each train.

Answer 1

Distance = (Rate)(Time), so Time = Distance / Rate

 

Let x = speed of freight train

 

Then, x+20 = speed of passenger train

 

340 / (x+20) = 240 / x

 

340x = 240(x+20)

 

Divide both sides by 20:  17x = 12(x+20)

 

                                     17x = 12x + 240

 

                                       5x = 240     x = 48 MPH

 

                                                         x+20 = 68 MPH