document.write( "Question 1042396: A tank that hold 400 gallon of water can be filed by one pipe in 15 minutes and emptied by another pipe in 40 minutes. how mush time does it take to fill tank if both pipes are open? \n" ); document.write( "

Algebra.Com's Answer #657362 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+t+\"$ = the time in minutes to
\n" ); document.write( "fill the tank with both pipes open
\n" ); document.write( "------------------------------
\n" ); document.write( "Add the rate of filling of the filling pipe
\n" ); document.write( "and subtract the rate of emptying of
\n" ); document.write( "the other pipe
\n" ); document.write( "--------------------------------
\n" ); document.write( " $\"+1%2F15+-+1%2F40+=+1%2Ft+\"$
\n" ); document.write( "Multiply both sides by $\"+120t+\"$
\n" ); document.write( " $\"+8t+-+3t+=+120+\"$
\n" ); document.write( " $\"+5t+=+120+\"$
\n" ); document.write( " $\"+t+=+24+\"$
\n" ); document.write( "If both pipes are open, the tank fills in 24 min
\n" ); document.write( "-------------------
\n" ); document.write( "check:
\n" ); document.write( " $\"+1%2F15+-+1%2F40+=+1%2F24+\"$
\n" ); document.write( " $\"+.06667+-+.025+=+.041667+\"$
\n" ); document.write( " $\"+.04167+=+.041667+\"$
\n" ); document.write( "error due to rounding off \n" ); document.write( "

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