document.write( "Question 809804: Mary drove to work at 40mph and got to work 1 minute late next day she went at 45 mph and got There 1 minute early how far does she live \n" ); document.write( "

Algebra.Com's Answer #487789 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+d+\"$ = the distance she must drive
\n" ); document.write( "Let $\"+t+\"$ = driving time in hrs that gets her there on time
\n" ); document.write( "-------------
\n" ); document.write( " $\"+d+=+40%2A%28+t+%2B+1%2F60+%29+\"$
\n" ); document.write( " $\"+d+=+45%2A%28+t+-+1%2F60+%29+\"$
\n" ); document.write( "------------------
\n" ); document.write( "By substitution:
\n" ); document.write( " $\"+40%2A%28+t%2B1%2F60+%29+=+45%2A%28+t-1%2F60+%29+\"$
\n" ); document.write( " $\"+40t+%2B+40%2F60+=+45t+-+45%2F60+\"$
\n" ); document.write( " $\"+5t+=+85%2F60+\"$
\n" ); document.write( " $\"+5t+=+17%2F12+\"$
\n" ); document.write( " $\"+t+=+17%2F60+\"$
\n" ); document.write( "---------------
\n" ); document.write( " $\"+d+=+40%2A%28+t+%2B+1%2F60+%29+\"$
\n" ); document.write( " $\"+d+=+40%2A%28+17%2F60+%2B+1%2F60+%29+\"$
\n" ); document.write( " $\"+d+=+40%2A%28+18%2F60+%29+\"$
\n" ); document.write( " $\"+d+=+40%2A%283%2F10%29+\"$
\n" ); document.write( " $\"+d+=+12+\"$
\n" ); document.write( "She lives 12 mi away
\n" ); document.write( "check:
\n" ); document.write( " $\"+d+=+45%2A%28+t+-+1%2F60+%29+\"$
\n" ); document.write( " $\"+12+=+45%2A%28+t+-+1%2F60+%29+\"$
\n" ); document.write( " $\"+12+=+45t+-+45%2F60+\"$
\n" ); document.write( "Divide both sides by $\"+3+\"$
\n" ); document.write( " $\"+4+=+15t+-+15%2F60+\"$
\n" ); document.write( " $\"+4+=+15t+-+1%2F4+\"$
\n" ); document.write( " $\"+16+=+60t+-+1+\"$
\n" ); document.write( " $\"+60t+=+17+\"$
\n" ); document.write( " $\"+t+=+17%2F60+\"$
\n" ); document.write( "OK\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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