document.write( "Question 916641: John Jr. can construct 180 boxes in an hour. John Sr. can only construct 20 boxes in an hour. Working together, how many minutes will it take them to construct 600 boxes? \n" ); document.write( "

Algebra.Com's Answer #556167 by josmiceli(19441) $\"\"$ $\"About$

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Add their rates of working to get
\n" ); document.write( "their rate working together
\n" ); document.write( "John Jr's rate: ( 180 boxes ) / ( 1 hr )
\n" ); document.write( "John Sr's rate: ( 20 boxes ) / ( 1 hr )
\n" ); document.write( "--------------------------------
\n" ); document.write( "Let $\"+t+\"$ = time in hrs for them to
\n" ); document.write( "construct $\"+600+\"$ boxes working
\n" ); document.write( "together
\n" ); document.write( "-----------------
\n" ); document.write( " $\"+180%2F1+%2B+20%2F1+=+600+%2F+t+\"$
\n" ); document.write( "Multiply both sides by $\"+t+\"$
\n" ); document.write( " $\"+180t+%2B+20t+=+600+\"$
\n" ); document.write( " $\"+200t+=+600+\"$
\n" ); document.write( " $\"+t+=+3+\"$
\n" ); document.write( " $\"+3%2A60+=+180+\"$
\n" ); document.write( "It will take them 180 min working together
\n" ); document.write( "check:
\n" ); document.write( " $\"+180%2F1+%2B+20%2F1+=+600+%2F+3+\"$
\n" ); document.write( " $\"+200+=+600%2F3+\"$
\n" ); document.write( " $\"+200+=+200+\"$
\n" ); document.write( "OK\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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