document.write( "Question 1197454: please help my friend's homework hehe thankyou
\n" ); document.write( "Mike and gerry can finish building a doghouse in 4 hours. It would take mike 6 more hours that gerry to finish the job working alone. How long would it take each boy if each works alone?
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Algebra.Com's Answer #830728 by ikleyn(52781)\"\" \"About 
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\n" ); document.write( "Mike and gerry can finish building a doghouse in 4 hours.
\n" ); document.write( "It would take mike 6 more hours \"highlight%28cross%28that%29%29\" THAN gerry to finish the job working alone.
\n" ); document.write( "How long would it take each boy if each works alone?
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\n" ); document.write( "\n" ); document.write( "Let  \"x\"  be the number of hours for gerry to cover the roof,  working alone.
\n" ); document.write( "If Mike works alone,  he can complete this job in  \"x%2B6\"  hours.
\n" ); document.write( "Thus,  in one single day Mike covers  \"1%2F%28x%2B6%29\"  part of the roof area,  while gerry covers  \"1%2Fx\"  part of the roof area.
\n" ); document.write( "Working together,  Mike and gerry make  \"1%2F%28x%2B6%29%2B1%2Fx\"  of the whole work in each single day.
\n" ); document.write( "Since they can cover the entire roof in  6  hours working together,  the equation for the unknown value  \"x\"  is as follows:\r
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\n" ); document.write( "\n" ); document.write( "        \"4%2F%28x%2B6%29+%2B+4%2Fx+=+1\".\r
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\n" ); document.write( "\n" ); document.write( "To simplify this equation,  multiply both sides by  \"%28x%2B6%29%2Ax\",  then transfer all terms
\n" ); document.write( "from the right side to the left with the opposite signs,  collect the common terms
\n" ); document.write( "and adjust the signs.  In this way you get\r
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\n" ); document.write( "\n" ); document.write( "        \"4x+%2B+4%28x%2B6%29+=+x%28x%2B6%29\",
\n" ); document.write( "        \"4x+%2B+4x+%2B24+=+x%5E2%2B6x\",
\n" ); document.write( "        \"x%5E2%2B6x-4x-4x-24+=+0\",
\n" ); document.write( "        \"x%5E2-2x-24+=+0\",\r
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\n" ); document.write( "\n" ); document.write( "You get the quadratic equation.  It is factorable\r
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\n" ); document.write( "\n" ); document.write( "        (x-6)*(x+4) = 0\r
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\n" ); document.write( "\n" ); document.write( "The equation has two roots:  \"x%5B1%5D=+6\"  and  \"x%5B2%5D=+-4\".
\n" ); document.write( "The second root  \"x%5B2%5D=+-2\"  makes no sense and we decline it. \r
\n" ); document.write( "\n" ); document.write( "So,  the potentially correct solution is  \"x%5B1%5D=+6\":  gerry covers the roof in  6  hours working alone.
\n" ); document.write( "Hence, Mike can complete the job in 6+6 = 12 hours.\r
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\n" ); document.write( "\n" ); document.write( "Let us check it. \r
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\n" ); document.write( "\n" ); document.write( "Since  \"4%2F12%2B4%2F6\" = \"1%2F3+%2B+2%2F3\" = \"1\",  this solution is correct.\r
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\n" ); document.write( "\n" ); document.write( "Answer.  gerry can finish the job in  6  hours working alone.  Mike can complete the job in  12  hours.\r
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\n" ); document.write( "\n" ); document.write( "Solved.\r
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