document.write( "Question 577635: chris can mow the lawn in 2 hours and 23 minutes. Jim can mow the lawn in 3 hours and 15 minutes. If they work together, how long will it take them to mow the lawn. I tried to average the times but I got the answer wrong. \n" ); document.write( "

Algebra.Com's Answer #370234 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Add their rates of mowing to get thir
\n" ); document.write( "rate working together
\n" ); document.write( "Chris's rate: ( 1 lawn ) / ( 2 hrs, 23 min )
\n" ); document.write( "Jim's rate: ( 1 lawn ) / ( 3 hrs 15 min )
\n" ); document.write( "Let $\"+t+\"$ = time in minutes for them
\n" ); document.write( "to mow lawn together
\n" ); document.write( "------------------
\n" ); document.write( " $\"+2%2A60+%2B+23+=+143+\"$
\n" ); document.write( " $\"+3%2A60+%2B+15+=+195+\"$
\n" ); document.write( " $\"+1%2F143+%2B+1%2F195+=+1%2Ft+\"$
\n" ); document.write( "Multiply both sides by $\"+143%2A195%2At+\"$
\n" ); document.write( " $\"+195t+%2B+143t+=+143%2A195+\"$
\n" ); document.write( " $\"+338t+=+27885+\"$
\n" ); document.write( " $\"+t+=+27885%2F338+\"$
\n" ); document.write( " $\"+t+=+82.5+\"$
\n" ); document.write( " $\"+82.5+-+60+=+22.5+\"$
\n" ); document.write( "Working together, it takes them 1 hr and 22.5 min
\n" ); document.write( "check:
\n" ); document.write( " $\"+1%2F143+%2B+1%2F195+=+1%2F82.5+\"$
\n" ); document.write( " $\"+.006993+%2B+.0051282+=+.0121212+\"$
\n" ); document.write( " $\"+.0121212+=+.0121212+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );