document.write( "Question 683698: A freight train travelling at 30km/h is 150km ahead of an express train travelling 60km/h. In how many hours will the express train overtake the freight train? \n" ); document.write( "

Algebra.Com's Answer #423659 by josmiceli(19441) $\"\"$ $\"About$

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Start a stopwatch when the express train leaves.
\n" ); document.write( "Now both will travel for the same amount
\n" ); document.write( "of time, $\"+t+\"$ in hrs, until the express train
\n" ); document.write( "overtakes the freight train.
\n" ); document.write( "Let $\"+d+\"$ = the distance the express train has to go
\n" ); document.write( "in km until they meet.
\n" ); document.write( "-------------
\n" ); document.write( "Equation for freight train:
\n" ); document.write( "(1) $\"+d+-+150+=+30t+\"$
\n" ); document.write( "Equation for express train:
\n" ); document.write( "(2) $\"+d+=+60t+\"$
\n" ); document.write( "---------------
\n" ); document.write( "Substitute (2) into (1)
\n" ); document.write( "(1) $\"+60t+-+150+=+30t+\"$
\n" ); document.write( "(1) $\"+30t+=+150+\"$
\n" ); document.write( "(1) $\"+t+=+5+\"$
\n" ); document.write( "The express train will overtake the freight train in 5 hrs
\n" ); document.write( "check answer:
\n" ); document.write( "(2) $\"+d+=+60%2A5+\"$
\n" ); document.write( "(2) $\"+d+=+300+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+d+-+150+=+30%2A5+\"$
\n" ); document.write( "(1) $\"+d+=+150+%2B+150+\"$
\n" ); document.write( "(1) $\"+d+=+300+\"$
\n" ); document.write( "OK\r
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