document.write( "Question 546739: A towns old street sweeper can clean the streets in 60h. The old sweeper together with the new sweeper can clean the street in 15h. How long would it take the new one to do the job alone? \n" ); document.write( "

Algebra.Com's Answer #356109 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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A towns old street sweeper can clean the streets in 60h. The old sweeper together with the new sweeper can clean the street in 15h. How long would it take the new one to do the job alone?
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\n" ); document.write( "Let n = new sweeper's time working alone
\n" ); document.write( "Let a completed job = 1 (a swept street)
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\n" ); document.write( " $\"15%2F60\"$ + $\"15%2Fn\"$ = 1
\n" ); document.write( "Reduce the fraction
\n" ); document.write( " $\"1%2F4\"$ + $\"15%2Fn\"$ = 1
\n" ); document.write( "mult by 4n
\n" ); document.write( "n + 4(15) = 4n
\n" ); document.write( "60 = 4n - n
\n" ); document.write( "60 = 3n
\n" ); document.write( "n = 60/3
\n" ); document.write( "n = 20 hrs \n" ); document.write( "

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