SOLUTION: At 8am a freight train leaves River City and heads for Rockville. At the same time a passenger train leaves Rockville and heads toward River City on parallel tracks. The passenger

Question 687256: At 8am a freight train leaves River City and heads for Rockville. At the same time a passenger train leaves Rockville and heads toward River City on parallel tracks. The passenger train avgs 50 mph faster than the freight train. The two trains pass each other at noon. If River City and Rockville are 520 miles apart, what is the avg speed of each train?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = the speed of the freight train in mi/hr
= the speed of the passenger train in mi/hr
Let = the distance in miles that the freight train
travels until it meets the passenger train
= the distance in miles that the passenger train
travels until it meets the freight train
The time the both trains travels until they meet is
hrs
---------------------
Equation for the freight train:
(1)
Equation for the passenger train:
(2)
--------------------------
(2)
Substitute (1) into (2)
(2)
(2)
(2)
(2)
and, since
(1)
(1)
(1)
and

The speed of the freight train is 40 mi/hr
The speed of the passenger train is 90 mi/hr
check:
(2)
(2)
(2)
(2)
(2)
OK

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