document.write( "Question 723737: It takes Mr. Jhonson 84 minutes to clean the cafeteria by himself. It takes Ms. Lopez 70 minutes. How long will it take if they work together \n" ); document.write( "

Algebra.Com's Answer #443329 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Add their rates of working
\n" ); document.write( "( 1 cafe cleaned ) / ( 84 min ) + ( 1 cafe cleaned ) / ( 70 min ) = ( 1 cafe cleaned ) / t
\n" ); document.write( "where $\"+t+\"$ = time in min if they work together
\n" ); document.write( " $\"+1%2F84+%2B+1%2F70+=+1%2Ft+\"$
\n" ); document.write( "Multiply both sides by $\"+70%2A84t+\"$
\n" ); document.write( " $\"+70t+%2B+84t+=+70%2A84+\"$
\n" ); document.write( " $\"+154t+=+5880+\"$
\n" ); document.write( " $\"+t+=+38.1818+\"$ min
\n" ); document.write( "This is about 38 min 11 sec working together
\n" ); document.write( " \n" ); document.write( "

\n" );