document.write( "Question 728479: A train goes from New Orleans to Boston at a speed of 40 mph. On the return journey it moves at a speed of 80 mph. If the return journey takes an hour less than the outward journey, what is the average speed overall of the train? \n" ); document.write( "

Algebra.Com's Answer #445478 by josmiceli(19441) $\"\"$ $\"About$

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Average speed = ( total distance ) / ( total time )
\n" ); document.write( "1st trip:
\n" ); document.write( " $\"+d+=+40t+\"$
\n" ); document.write( "2nd trip:
\n" ); document.write( " $\"+d+=+80%2A%28+t+-+1+%29+\"$
\n" ); document.write( "-----------------
\n" ); document.write( "By sustitution:
\n" ); document.write( " $\"+40t+=+80%2A%28+t+-+1+%29+\"$
\n" ); document.write( " $\"+40t+=+80t+-+80+\"$
\n" ); document.write( " $\"+40t+=+80+\"$
\n" ); document.write( " $\"+t+=+2+\"$
\n" ); document.write( "----------
\n" ); document.write( " $\"+d+=+40t+\"$
\n" ); document.write( " $\"+d+=+40%2A2+\"$
\n" ); document.write( " $\"+d+=+80+\"$
\n" ); document.write( "The distance traveled is $\"+2d+\"$
\n" ); document.write( " $\"+2d+=+160+\"$
\n" ); document.write( "The total time is $\"+t+%2B+t+-+1+=+2%2A2+-+1+\"$
\n" ); document.write( " $\"+2%2A2+-+1+=+3+\"$
\n" ); document.write( "----------------
\n" ); document.write( "( total distance ) / ( total time ) = $\"+160%2F3+\"$
\n" ); document.write( " $\"+160%2F3+=+53.333+\"$
\n" ); document.write( "The average speed is 53.333 mi/hr
\n" ); document.write( " \n" ); document.write( "

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