document.write( "Question 878209: Together, Mary and John can write a particular type of computer program in 15 hours. Alone, Mary can
\n" ); document.write( "do the job 3 hours faster than John. Find the time that each person takes to write a computer program.\r
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Algebra.Com's Answer #529752 by josmiceli(19441) $\"\"$ $\"About$

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Add their rates of working
\n" ); document.write( "Together:
\n" ); document.write( "( 1 program ) / ( 15 hrs )
\n" ); document.write( "John alone:
\n" ); document.write( "( 1 program ) / ( t hrs )
\n" ); document.write( "Mary alone:
\n" ); document.write( "( 1 program ) / ( t - 3 )
\n" ); document.write( "---------------------
\n" ); document.write( " $\"+1%2Ft+%2B+1%2F%28+t-3+%29+=+1%2F15+\"$
\n" ); document.write( "Multiply both sides by $\"+15%2At%2A%28+t-3+%29+\"$
\n" ); document.write( " $\"+15%2A%28+t-3+%29+%2B+15t+=+t%2A%28+t-3+%29+\"$
\n" ); document.write( " $\"+15t+-+45+%2B+15t+=+t%5E2+-+3t+\"$
\n" ); document.write( " $\"+t%5E2+-+33t+%2B+45+=+0+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( "Solve for $\"+t+\"$ with quadratic formula
\n" ); document.write( "then find $\"+t+\"$ and $\"+t+-+3+\"$ \r
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