document.write( "Question 796733: It requires 5 hrs for Margaret to paint a building. If she and Sam work together, they can paint the same building in 3 hours. Find the time, in hours, it would take Sam to paint the building alone. \n" ); document.write( "

Algebra.Com's Answer #481540 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+t+\"$ = time in hrs for Sam to paint building alone
\n" ); document.write( "Margaret's rate: ( 1 building ) / ( 5 hrs )
\n" ); document.write( "Margaret and Sam together: ( 1 building ) / ( 3 hrs )
\n" ); document.write( "-------------
\n" ); document.write( "Add their rates to get rate working together
\n" ); document.write( " $\"+1%2F5+%2B+1%2Ft+=+1%2F3+\"$
\n" ); document.write( "Multiply both sides by $\"+15t+\"$
\n" ); document.write( " $\"+3t+%2B+15+=+5t+\"$
\n" ); document.write( " $\"+2t+=+15+\"$
\n" ); document.write( " $\"+t+=+7.5+\"$
\n" ); document.write( "-----------
\n" ); document.write( "Sam can paint the building alone in 7.5 hrs
\n" ); document.write( "check:
\n" ); document.write( " $\"+1%2F5+%2B+1%2Ft+=+1%2F3+\"$
\n" ); document.write( " $\"+.2+%2B+1%2F7.5+=+.333+\"$
\n" ); document.write( " $\"+.2+%2B+.1333+=+.333+\"$
\n" ); document.write( " $\"+.333+=+.333+\"$
\n" ); document.write( "OK\r
\n" ); document.write( "
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