<PRE><B>Question 858763</B>
If a passenger train travels three times as fast as a freight train, and the freight train takes 4 hours longer to travel 210 miles. What is the speed of each train?
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let x=speed of freight train
3x=speed of passenger train
travel time =distance/speed
...
{{{210/x-210/3x=4}}}
LCD:3x
630-210=12x
12x=420
x=35
3x=105
speed of freight train=35 mph
speed of passenger train=105 mph</PRE>