document.write( "Question 615267: After a heavy snowfall, Brian can shovel the entire driveway in 30 minutes. If his brother Alan helps, the job takes only 20 minutes. How long would it take Alan to do the job by himself? \n" ); document.write( "

Algebra.Com's Answer #387042 by josmiceli(19441) $\"\"$ $\"About$

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You must add their rates of working to get
\n" ); document.write( "their rate working together
\n" ); document.write( "Brian's rate: ( 1 driveway ) / ( 30 min )
\n" ); document.write( "Brian's rate + Alan's rate: ( 1 driveway ) / ( 20 min )
\n" ); document.write( "Let Alan's rate working alone = ( 1 driveway / x min )
\n" ); document.write( "-------------
\n" ); document.write( " $\"+1%2F30+%2B+1%2Fx+=+1%2F20+\"$
\n" ); document.write( "Multiply both sides by $\"+60x+\"$
\n" ); document.write( " $\"+2x+%2B+60+=+3x+\"$
\n" ); document.write( " $\"+x+=+60+\"$
\n" ); document.write( "Alan can do the job alone in 1 hour
\n" ); document.write( " \n" ); document.write( "

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