document.write( "Question 565784: Train A leaves a station traveling at 20 mph. Four hours later train B leaves the same station traveling in the same direction at 30 mph How long does it take for train B to catch up to train A? \n" ); document.write( "
Algebra.Com's Answer #365988 by ankor@dixie-net.com(22740)\"\" \"About 
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Train A leaves a station traveling at 20 mph.
\n" ); document.write( " Four hours later train B leaves the same station traveling in the same direction at 30 mph
\n" ); document.write( "How long does it take for train B to catch up to train A?
\n" ); document.write( ":
\n" ); document.write( "Let t = travel time of train B when it catches A
\n" ); document.write( "then
\n" ); document.write( "(t+4) = travel time of train A when it's caught
\n" ); document.write( ":
\n" ); document.write( "When this occurs they will have traveled the same distance.
\n" ); document.write( "Write a distance equation: dist = speed * time
\n" ); document.write( ":
\n" ); document.write( "30t = 20(t+4)
\n" ); document.write( "30t = 20t + 80
\n" ); document.write( "30t - 20t = 80
\n" ); document.write( "10t = 80
\n" ); document.write( "t = 80/10
\n" ); document.write( "t = 8 hrs for B to catch A
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Confirm this by finding the distance of each train
\n" ); document.write( "30*8 = 240 mi
\n" ); document.write( "20*12 =240 mi \n" ); document.write( "
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