document.write( "Question 460609: it takes kevin 3 hours more than john to paint a fence. together they painted for 3 hours, than kevin left and john finished the job in one additional hour. find how long it would take each boy to paint the fence alone? \n" ); document.write( "

Algebra.Com's Answer #315973 by lwsshak3(11628) $\"\"$ $\"About$

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it takes kevin 3 hours more than john to paint a fence. together they painted for 3 hours, than kevin left and john finished the job in one additional hour. find how long it would take each boy to paint the fence alone?
\n" ); document.write( "..\r
\n" ); document.write( "\n" ); document.write( "let x= hrs John takes to finish the job alone
\n" ); document.write( "1/x=John's work rate
\n" ); document.write( "x+3 =hrs Kevin takes to finish the job alone
\n" ); document.write( "1/(x+3)=Kevin's work rate
\n" ); document.write( "..
\n" ); document.write( "Kevin worked for 3 hours
\n" ); document.write( "John worked for 4 hours
\n" ); document.write( "3/(x+3)+4/x)=100%=1
\n" ); document.write( "LCD:x(x+3)
\n" ); document.write( "3x+4x+12=x(x+3)=x^2+3x
\n" ); document.write( "x^2-4x-12=0
\n" ); document.write( "(x-6)(x+2)=0
\n" ); document.write( "x=6
\n" ); document.write( "or
\n" ); document.write( "x=-2 (reject,x>0)
\n" ); document.write( "..
\n" ); document.write( "ans:
\n" ); document.write( "John takes 6 hrs to paint the fence alone
\n" ); document.write( "Kevin takes 9 hrs to paint the fence alone \n" ); document.write( "

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