document.write( "Question 1108568: Jessica can wash the family dog in 45 minutes. Her brother can wash the dog in just 30 minutes. How long would it take them working together to wash the dog ? \n" ); document.write( "

Algebra.Com's Answer #723539 by josmiceli(19441) $\"\"$ $\"About$

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Jessica's rate of washing:
\n" ); document.write( "[ 1 dog washed ] / [ 45 min ]
\n" ); document.write( "Brother's rate of washing:
\n" ); document.write( "[ 1 dog washed ] / [ 30 min ]
\n" ); document.write( "Their rate working together:
\n" ); document.write( "[ 1 dog washed ] / [ t min ]
\n" ); document.write( "---------------------------
\n" ); document.write( "Add their rates of washing to get rate
\n" ); document.write( "washing together
\n" ); document.write( " $\"+1%2F45+%2B+1%2F30+=+1%2Ft+\"$
\n" ); document.write( "Multiply both sides by $\"+90t+\"$
\n" ); document.write( " $\"+2t+%2B+3t+=+90+\"$
\n" ); document.write( " $\"+5t+=+90+\"$
\n" ); document.write( " $\"+t+=+18+\"$
\n" ); document.write( "It will take them 18 min working together
\n" ); document.write( " \n" ); document.write( "

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