document.write( "Question 128173: It takes Tom 3 hours less to paint a fence than Jim. If the two boys work together, they can paint the fence in 2 hours. How many hours would each boy, working alone, need to paint the fence? \n" ); document.write( "
Algebra.Com's Answer #93852 by marcsam823(57)\"\" \"About 
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1. Set up the variables:
\n" ); document.write( "Let x = # hours it takes Jim to paint the fence alone
\n" ); document.write( "Let x - 3 = # hours it takes Tom to paint the fence alone
\n" ); document.write( "Let 1/x = amount of the fence painted by Jim in 1 hour
\n" ); document.write( "Let \"1%2F%28x+-+3%29\" = amount of the fence painted by Tom in 1 hour\r
\n" ); document.write( "\n" ); document.write( "2. Set up the equation(s)
\n" ); document.write( "In 1 hour the two boys paint
\n" ); document.write( "\"1%2Fx+%2B+1%2F%28x-3%29\" of the fence\r
\n" ); document.write( "\n" ); document.write( "In 2 hours the two boys paint:
\n" ); document.write( "\"2=+1\" (1 = 1 job or 100% of the job)
\n" ); document.write( "\"2%2Fx+%2B+2%2F%28x-3%29=+1\"
\n" ); document.write( "3. Find the common denominator: (x)(x-3)= \"x%5E2+-+3x\"
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\n" ); document.write( "4. Multiply both sides of the equation by (x^2 - 3x):
\n" ); document.write( "\"2%28x-3%29+%2B+2x+=+x%5E2+-+3x\"
\n" ); document.write( "5. Combine like terms:
\n" ); document.write( "\"2x+-+6++%2B+2x+=+x%5E2+-+3x\"
\n" ); document.write( "\"4x+-+6+=+x%5E2+-+3x\"
\n" ); document.write( "\"0+=+x%5E2+-+7x+%2B+6\"
\n" ); document.write( "6. Factor and solve for x:
\n" ); document.write( "\"%28x+-+1%29%28x+-+6%29+=+0\"
\n" ); document.write( "\"x+=+1\" or \"x+=+6\"
\n" ); document.write( "Since we have two answers we need to see which one makes sense by plugging each into our equations:
\n" ); document.write( "Jim can paint a fence in x = 1 hours
\n" ); document.write( "Tom can paint a fence in x-3 = -2 hours
\n" ); document.write( "We must reject this answer because time can never be a negative value.
\n" ); document.write( "Substitute x = 6:
\n" ); document.write( "Jim can paint the fence in \"x+=+6\" hours
\n" ); document.write( "Tom can paint the fence in \"x+-+3+=+6+-+3+=+3\" hours
\n" ); document.write( "This is the answer we are looking for.\r
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