Problema Solution

a freight train leave the train station 4 hours before a passenger train. the two trains are traveling in the same direction on parallel track. if the rate of the passenger train is 40mph faster than the freight train, how fast is each train traveling if the passenger train passes the freight train in 4 hours

Answer provided by our tutors

let


v1 = the speed of the freight train


t1 = the time of the freight train


v2 = the speed of the passenger train


t2 = 4 hr the time of the passenger train


a freight train leave the train station 4 hours before a passenger train:


t1 = t2 + 4


t1 = 4 + 4


t1 = 8 hr


the rate of the passenger train is 40mph faster than the freight train:


v2 = v1 + 40


since they both pass the same distance and distance = speed*time we have


v1*t1 = v2*t2


8*v1 = 4*v2 divide both sides by 8


2v1 = v2


by solving the system of equations:


v2 = v1 + 40


2v1 = v2


we find:


v1 = 40 mph


v2 = 80 mph


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the speed of the freight train is 40 mph.


the speed of the passenger train is 80 mph.