document.write( "Question 258979: If joe can paint a fence in 3hrs. and jack can paint it in 4hrs. How long will it take them to paint it together. \n" ); document.write( "

Algebra.Com's Answer #190673 by drk(1908) $\"\"$ $\"About$

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This is a working together or job / time problem. We use the following formula
\n" ); document.write( "(J1/T1)(x) + (J2/T2)(x) = TJ
\n" ); document.write( "where
\n" ); document.write( "J1 = person 1's job
\n" ); document.write( "T1 = person 1's time
\n" ); document.write( "J2 = person 2's job
\n" ); document.write( "T2 = person 2's time
\n" ); document.write( "x = time together
\n" ); document.write( "TJ = total number of jobs
\n" ); document.write( "--
\n" ); document.write( "From the given information we get
\n" ); document.write( " $\"%281%2F3%29%28x%29+%2B+%281%2F4%29%28x%29+=+1\"$
\n" ); document.write( "--
\n" ); document.write( "step 1 - multiply by 12 to get
\n" ); document.write( " $\"4x+%2B+3x+=+12\"$
\n" ); document.write( "step 2 combine like terms to get
\n" ); document.write( " $\"7x+=+12\"$
\n" ); document.write( "step 3 - divide to get
\n" ); document.write( " $\"x+=+12%2F7\"$
\n" ); document.write( "So it will take them together 12/7 hrs or ~ 1.71 hours \n" ); document.write( "

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