document.write( "Question 737631: Mary walks at 4 mph. sarah jogos 10 mph. if they both leave the school at 8 am going along the same path in the same direction, at what time will they be 9 miles apart? \n" ); document.write( "

Algebra.Com's Answer #450462 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+d+\"$ = Sarah's distance when they are 9 mi apart
\n" ); document.write( " $\"+d+-+9+\"$ = Mary's distance when they are 9 mi apart
\n" ); document.write( "Let $\"+t+\"$ = time in hrs passed after 8 AM when they are 9 mi apart
\n" ); document.write( "-------------
\n" ); document.write( "Sarah's equation:
\n" ); document.write( "(1) $\"+d+=+10t+\"$
\n" ); document.write( "Mary's equation:
\n" ); document.write( "(2) $\"+d+-+9+=+4t+\"$
\n" ); document.write( "------------
\n" ); document.write( "(2) $\"+d+=+9+%2B+4t+\"$
\n" ); document.write( "By substitution:
\n" ); document.write( "(2) $\"+10t+=+9+%2B+4t+\"$
\n" ); document.write( "(2) $\"+6t+=+9+\"$
\n" ); document.write( "(2) $\"+t+=+3%2F2+\"$ '
\n" ); document.write( "8 AM + 3/2 hrs = 9:30 AM
\n" ); document.write( "check:
\n" ); document.write( "(1) $\"+d+=+10%2A%283%2F2%29+\"$
\n" ); document.write( "(1) $\"+d+=+15+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+d+-+9+=+4%2A%283%2F2%29+\"$
\n" ); document.write( "(2) $\"+d+=+9+%2B+6+\"$
\n" ); document.write( "(2) $\"+d+=+15+\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

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