document.write( "Question 870238: Three postal workers can sort a stack of mail in 10 minutes, 20 minutes, and 60 minutes, respectively. How long will it take all three to sort a stack of mail working together? \n" ); document.write( "

Algebra.Com's Answer #524744 by josmiceli(19441) $\"\"$ $\"About$

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Add their rates of sorting
\n" ); document.write( "1st workers rate:
\n" ); document.write( "( 1 stack ) / ( 10 min )
\n" ); document.write( "2nd worker's rate:
\n" ); document.write( "( 1 stack ) / ( 20 min )
\n" ); document.write( "3rd worker's rate:
\n" ); document.write( "( 1 stack ) / ( 60 min )
\n" ); document.write( "-------------------------
\n" ); document.write( "Let $\"+t+\"$ = the time in minutes
\n" ); document.write( "for all three to sort the stack
\n" ); document.write( " $\"+1%2F10+%2B+1%2F20+%2B+1%2F60+=+1%2Ft+\"$
\n" ); document.write( "Multiply both sides by $\"+60t+\"$
\n" ); document.write( " $\"+6t+%2B+3t+%2B+t+=+60+\"$
\n" ); document.write( " $\"+10t+=+60+\"$
\n" ); document.write( " $\"+t+=+6+\"$
\n" ); document.write( "---------------
\n" ); document.write( "All three sorting together will take
\n" ); document.write( "6 min to sort the stack of mail
\n" ); document.write( " \n" ); document.write( "

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