document.write( "Question 1012188: Rob takes 9 hours to clean the attic.
\n" ); document.write( "Huong can clean the same attic in 15 hours.
\n" ); document.write( "How long would it take if they worked together? \n" ); document.write( "

Algebra.Com's Answer #628055 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Add their rates of working to get their
\n" ); document.write( "rate of working together
\n" ); document.write( "Rob's rate:
\n" ); document.write( "[ 1 attic cleaned ] / [ 9 hrs ]
\n" ); document.write( "Huong's rate:
\n" ); document.write( "[ 1 attic cleaned ] / [ 15 hrs ]
\n" ); document.write( "--------------------------
\n" ); document.write( "Let their rate working together =
\n" ); document.write( "[ 1 attic cleaned ] / [ t hrs ]
\n" ); document.write( " $\"+1%2F9+%2B+1%2F15+=+1%2Ft+\"$
\n" ); document.write( "Multiply both sides by $\"+45t+\"$
\n" ); document.write( " $\"+5t+%2B+3t+=+45+\"$
\n" ); document.write( " $\"+8t+=+45+\"$
\n" ); document.write( " $\"+t+=+5.625+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+.625%2A60+=+37.5+\"$
\n" ); document.write( "Working together, it will take them
\n" ); document.write( "5 hrs 37 min 30 sec
\n" ); document.write( " \n" ); document.write( "

\n" );