document.write( "Question 744030: one printing machine works twice as fast as another. When both machines are used, they can print a magazine in 3 hrs. How many hours would each machine require to do the job alone?
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Algebra.Com's Answer #453146 by josmiceli(19441) $\"\"$ $\"About$

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Add their rates of printing
\n" ); document.write( "Let $\"+r+\"$ = the slower machine's rate of printing
\n" ); document.write( " $\"+2r+\"$ = the faster machine's rate of printing
\n" ); document.write( "When both machines are used, their rate of printing is
\n" ); document.write( "( 1 magazine ) / ( 3 hrs )
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\n" ); document.write( " $\"+r+%2B+2r+=+1%2F3+\"$
\n" ); document.write( " $\"+3r+=+1%2F3+\"$
\n" ); document.write( " $\"+r+=+1%2F9+\"$
\n" ); document.write( " $\"+2r+=+2%2F9+\"$
\n" ); document.write( " $\"+2r+=+1%2F4.5+\"$
\n" ); document.write( "The fast machine can print a magazine in 4.5 hrs
\n" ); document.write( "The slow machine can print a magazine in 9 hrs
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