document.write( "Question 746009: one pump can drain a pool in 7 minutes. When a second pump is also used together with the first, the pool only takes 3 minutes to drain. How long would it take the second pump to drain the pool if it were the only pump in use? \n" ); document.write( "

Algebra.Com's Answer #454107 by josmiceli(19441) $\"\"$ $\"About$

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Add their rates of draining to get their
\n" ); document.write( "rate of draining together
\n" ); document.write( "( 1 pool / 7 min ) + ( 1 pool / t min ) = ( 1 pool / 3 )
\n" ); document.write( "Solve for $\"+t+\"$
\n" ); document.write( " $\"+1%2F7+%2B+1%2Ft+=+1%2F3+\"$
\n" ); document.write( "Multiply both sides by $\"+21t+\"$
\n" ); document.write( " $\"+3t+%2B+21+=+7t+\"$
\n" ); document.write( " $\"+4t+=+21+\"$
\n" ); document.write( " $\"+t+=+5.25+\"$
\n" ); document.write( " $\"+.25%2A60+=+15+\"$
\n" ); document.write( "It will take the 2nd pump
\n" ); document.write( "5 min and 15 sec by itself
\n" ); document.write( " \n" ); document.write( "

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