document.write( "Question 640690: Jack can paint a housw twice as fast as Jill. Jill starts at 8 AM, Jacj joins in at 10 AM. They finished at 2 PM. How long does it take each of them to paint the house by themself?
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Algebra.Com's Answer #403366 by nerdybill(7384) $\"\"$ $\"About$

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Jack can paint a house twice as fast as Jill. Jill starts at 8 AM, Jacj joins in at 10 AM. They finished at 2 PM. How long does it take each of them to paint the house by themself?
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\n" ); document.write( "Let x = time (hours) it takes for Jack to paint house
\n" ); document.write( "then
\n" ); document.write( "2x = time (hours) it takes for Jill to paint house
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\n" ); document.write( "Jill has a 2 hour head start
\n" ); document.write( "then, they both paint for an additional 4 hours
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\n" ); document.write( "2(1/(2x)) + 4(1/x + 1/(2x)) = 1
\n" ); document.write( "multiplying both sides by 2x:
\n" ); document.write( "2(1) + 4(2 + 1) = 2x
\n" ); document.write( "2 + 4(3) = 2x
\n" ); document.write( "2 + 12 = 2x
\n" ); document.write( "14 = 2x
\n" ); document.write( "7 hours = x (time it takes for Jack to paint the house alone)
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\n" ); document.write( "Jill:
\n" ); document.write( "2x = 2(7) = 14 hours
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