document.write( "Question 674345: anthony can build a wall in 10 hours. his helper can do it in 15 hours. how long will it take them working together, assuming that each works at his own rate?
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Algebra.Com's Answer #419170 by josmiceli(19441) $\"\"$ $\"About$

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Add their rates of working
\n" ); document.write( "Anthony's rate is ( 1 wall ) / ( 10 hrs )
\n" ); document.write( "Helper's rate is ( 1 wall ) / ( 15 hrs )
\n" ); document.write( "Let $\"+t+\"$ = time in hours for them to do it together
\n" ); document.write( " $\"+1%2F10+%2B+1%2F15+=+1%2Ft+\"$
\n" ); document.write( "Multiply both sides by $\"+30t+\"$
\n" ); document.write( " $\"+3t+%2B+2t+=+30+\"$
\n" ); document.write( " $\"+5t+=+30+\"$
\n" ); document.write( " $\"+t+=+6+\"$
\n" ); document.write( "It takes them 6 hrs working together
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