document.write( "Question 739251: Dave and Sandy can paint a room together in 4 hrs. Working alone, Dave can paint the room in 2 hrs less time than Sandy can. Find how long it takes Sandy to paint the room alone. \n" ); document.write( "
Algebra.Com's Answer #451074 by checkley79(3341)\"\" \"About 
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1/X+1/(X+2)=1/4
\n" ); document.write( "(X+2+X)/X(X+2)=1/4
\n" ); document.write( "(2X+2)/(X^2+2X)=1/4 CROSS MULTIPLY.
\n" ); document.write( "X^2+2X=4(2X+2)
\n" ); document.write( "X^2+2X=8X+8
\n" ); document.write( "X^2+2X-8X-8=0
\n" ); document.write( "X^2-6X-8=0
\n" ); document.write( " \"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "X=(6+-SQRT(-6^2-4*1*-8))/2*1
\n" ); document.write( "X=(6+-SQRT(36+32)/2
\n" ); document.write( "X=(6+-SQRT68)/2
\n" ); document.write( "X=(6+-8.246)/2
\n" ); document.write( "X=(6+8.246)/2
\n" ); document.write( "X=14.246/2
\n" ); document.write( "X=7.123 HOURS FOR DAVE.
\n" ); document.write( "7.123+2=9.123 HOURS FOR SANDY.
\n" ); document.write( "PROOF:
\n" ); document.write( "1/7.123+1/9.123=1/4
\n" ); document.write( "(9.123+7.123)/(7.123*9.123)=1/4
\n" ); document.write( "16.246/64.96=1/4
\n" ); document.write( "1/4=1/4
\n" ); document.write( " \n" ); document.write( "
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