document.write( "Question 706228: a pipe can fill a tank in 12 hours and another can empty in 24 hours. if both the pipes are used, with the first pipe running for 2 hours and second pipe running for 1 hour, alternatively, starting with the first pipe, then how long will it take to fill the tank \n" ); document.write( "

Algebra.Com's Answer #435030 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
In other words, every 3 hours, the 1st pipe fills for 2 hours
\n" ); document.write( "and the 2nd pipe empties for 1 hour.
\n" ); document.write( "Let $\"+3t+\"$ = time in hours to fill the tank
\n" ); document.write( " $\"+2t+\"$ will be the 1st pipe's time filling
\n" ); document.write( " $\"+t+\"$ will be the 2nd pipe's time emptying
\n" ); document.write( "-----------
\n" ); document.write( "( 1 tank ) / ( 12 hrs ), or $\"+1%2F12+\"$ is the 1st pipe's rate
\n" ); document.write( "( 1 tank ) / ( 24 hrs ) or $\"+1%2F24+\"$ is the 2nd pipe's rate
\n" ); document.write( "-----------
\n" ); document.write( "Note that (rate)x(time) = fraction of tank filled or emptied
\n" ); document.write( " $\"+%281%2F12%29%2A2t+-+%281%2F24%29%2At+=+1+\"$
\n" ); document.write( "This says ( fraction of tank filled ) - ( fraction emptied ) = ( 1 tank filled )
\n" ); document.write( "Divide both sides by $\"+t+\"$
\n" ); document.write( " $\"+2%2F12+-+1%2F24+=+1%2Ft+\"$
\n" ); document.write( " $\"+4%2F24+-+1%2F24+=+1%2Ft+\"$
\n" ); document.write( " $\"+3%2F24+=+1%2Ft+\"$
\n" ); document.write( " $\"+1%2F8+=+1%2Ft+\"$
\n" ); document.write( " $\"+t+=+8+\"$
\n" ); document.write( " $\"+3t+=+24+\"$
\n" ); document.write( "It will take 24 hrs to fill the tank
\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );