document.write( "Question 1091243: Mark working alone can do 2 jobs in m hours, and Bob working alone can do 2 jobs in b hours. How long will it take Mark and Bob to do one job if they work together? \n" ); document.write( "

Algebra.Com's Answer #705642 by josmiceli(19441) $\"\"$ $\"About$

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Mark's rate is $\"+2%2Fm+\"$
\n" ); document.write( "Bob's rate is $\"+2%2Fb++\"$
\n" ); document.write( "Add their individual rates to get
\n" ); document.write( "their rate working together
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\n" ); document.write( "Let $\"+t+\"$ = their time in hrs to do 1 job working together
\n" ); document.write( " $\"+2%2Fm+%2B+2%2Fb+=+1%2Ft+\"$
\n" ); document.write( "Multiply both sides by $\"+m%2Ab%2At+\"$
\n" ); document.write( " $\"+2%2Ab%2At+%2B+2%2Am%2At+=+m%2Ab+\"$
\n" ); document.write( " $\"+%28+2b+%2B+2m+%29%2At+=+m%2Ab+\"$
\n" ); document.write( " $\"+t+=+%28+m%2Ab+%29%2F%28+2b+%2B+2m+%29+\"$ \r
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