document.write( "Question 832191: John can paint a wall in 9 days and Kyle paints the same wall in 15 days. Find out: a) how long it will take for John and Kyle to paint the wall together and b) if Kyle started painting the wall, and John joins after 5 days, how many additional days will it take them to complete the job \n" ); document.write( "

Algebra.Com's Answer #501917 by josmiceli(19441) $\"\"$ $\"About$

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Add their rates of painting to get their
\n" ); document.write( "rate painting together
\n" ); document.write( "( 1 wall / 9 days ) + ( 1wall / 15 days ) = ( 1 wall / x days )
\n" ); document.write( " $\"+1%2F9+%2B+1%2F15+=+1%2Fx+\"$
\n" ); document.write( "Multiply both sides by $\"+45x+\"$
\n" ); document.write( " $\"+5x+%2B+3x+=+45+\"$
\n" ); document.write( " $\"+8x+=+45+\"$
\n" ); document.write( " $\"+x+=+5.625+\"$
\n" ); document.write( "They can paint the wall in 5.625 days painting together
\n" ); document.write( "----------------------
\n" ); document.write( "If Kyle paints for $\"5\"$ days, I can say:
\n" ); document.write( " $\"+1%2F9+=+y%2F5+\"$
\n" ); document.write( " $\"+y+=+5%2F9+\"$
\n" ); document.write( "So, Kyle paints $\"5%2F9\"$ of the wall in $\"5\"$ days
\n" ); document.write( "There is $\"+1+-+5%2F9+=+4%2F9+\"$ of the wall left to paint
\n" ); document.write( "Now I can say:
\n" ); document.write( " $\"+1%2F9+%2B+1%2F15+=+%284%2F9%29%2Fz+\"$
\n" ); document.write( " $\"+5z+%2B+3z+=+45%2A%284%2F9%29+\"$
\n" ); document.write( " $\"+8z+=+20+\"$
\n" ); document.write( " $\"+z+=+2.5+\"$
\n" ); document.write( "It will take 2.5 more days to complete the job
\n" ); document.write( " \n" ); document.write( "

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