document.write( "Question 773257: Michael drove to a friends house at a rate of 40 mph. He returned by the same route at a rate of 45 mph. The driving time for the round trip was 4 hours. What is the distance Michael Traveled?\r
\n" ); document.write( "\n" ); document.write( "Please explain how you got this answer.
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Algebra.Com's Answer #471390 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+d+\"$ = the one-way distance to friends house
\n" ); document.write( "Let $\"+t+\"$ = time spent driving at $\"+40+\"$ mi/hr
\n" ); document.write( " $\"+4+-+t+\"$ = time spent driving at $\"+45+\"$ mi/hr
\n" ); document.write( "---------------
\n" ); document.write( "Equation for driving to house
\n" ); document.write( "(1) $\"+d+=+40t+\"$
\n" ); document.write( "Equation for driving back:
\n" ); document.write( "(2) $\"+d+=+45%2A%28+4+-+t+%29+\"$
\n" ); document.write( "--------------------
\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) $\"+40t+=+45%2A%28+4+-+t+%29+\"$
\n" ); document.write( "(2) $\"+40t+=+180+-+45t+\"$
\n" ); document.write( "(2) $\"+85t+=+180+\"$
\n" ); document.write( "(2) $\"+t+=+2.1176+\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"+d+=+40%2A2.1176+\"$
\n" ); document.write( "(1) $\"+d+=+84.706+\"$
\n" ); document.write( " $\"+2d+=+169.412+\"$
\n" ); document.write( "He traveled 169.412 miles\r
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