document.write( "Question 893133: when blake drives to work on the highway, he averages 45mph. when he uses the local roads he averages 36mph. the trip on the local roads is 3 mi shorter and takes 5 more minutes than the highway trip. how many miles long is the highway trip? \n" ); document.write( "
Algebra.Com's Answer #541096 by josmiceli(19441)\"\" \"About 
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Let \"+d+\" = the distance in miles he drives on highway
\n" ); document.write( "Let \"+t+\" = time in hours he spends on highway
\n" ); document.write( "--------------------------------------------
\n" ); document.write( "Now convert \"+5+\" minutes to hours
\n" ); document.write( "( minutes ) x ( hours / minute )
\n" ); document.write( "\"+5%2A%28+1%2F60+%29++=+1%2F12+\" hrs
\n" ); document.write( "--------------------------
\n" ); document.write( "Equation for driving on highway:
\n" ); document.write( "(1) \"+d+=+45t+\"
\n" ); document.write( "Equation for driving on local roads:
\n" ); document.write( "(2) \"+d+-+3+=+36%2A%28+t+%2B+1%2F12+%29+\"
\n" ); document.write( "(2) \"+d+=+36t+%2B+3+%2B+3+\"
\n" ); document.write( "(2) \"+d+=+36t+%2B+6+\"
\n" ); document.write( "--------------------
\n" ); document.write( "Substitute (1) into (2)
\n" ); document.write( "(2) \"+45t+=+36t+%2B+6+\"
\n" ); document.write( "(2) \"+9t+=+6+\"
\n" ); document.write( "(2) \"+t+=+2%2F3+\" hrs
\n" ); document.write( "and, since
\n" ); document.write( "(1) \"+d+=+45t+\"
\n" ); document.write( "(1) \"+d+=+45%2A%282%2F3%29+\"
\n" ); document.write( "(1) \"+d+=+30+\"
\n" ); document.write( "He drove 30 highway miles
\n" ); document.write( "-------------------------
\n" ); document.write( "check:
\n" ); document.write( "(2) \"+d+-+3+=+36%2A%28+t+%2B+1%2F12+%29+\"
\n" ); document.write( "(2) \"+30+-+3+=+36%2A%28+2%2F3+%2B+1%2F12+%29+\"
\n" ); document.write( "(2) \"+27+=+36%2A%28+8%2F12+%2B+1%2F12+%29+\"
\n" ); document.write( "(2) \"+27+=+36%2A%28+9%2F12+%29+\"
\n" ); document.write( "(2) \"+27+=+3%2A9+\"
\n" ); document.write( "(2) \"+27+=+27+\"
\n" ); document.write( "OK\r
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