Question

A passenger train leaves a train depot 1 hr after a freight train leaves the same depot . the freight train is travelling 15 mph slower than the passenger train. find the rate of each train if the passenger train overtakes the freight train in 3 hr.

Answer 1

the passenger train takes 3 hours to travel a distance
the freight train takes 4 hours to travel the same distance

say the speed of the passenger train is x
the speed of the freight train would therefore be x-15

speedxtime is distance

therefore you can form the equation:
(3)(x)=(4)(x-15)

solve for x, then find your solutions ^^