document.write( "Question 359395: it takes 4 hours to fill a tank it takes 6 hours to empty the tank how long dose it take to fill it if both vales are open \n" ); document.write( "

Algebra.Com's Answer #256699 by Fombitz(32388) $\"\"$ $\"About$

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Rate*Time=Output
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\n" ); document.write( "Let the tank volume be $\"V\"$ .
\n" ); document.write( "Find the fill rate,
\n" ); document.write( " $\"R%5Bf%5D%2At=V\"$
\n" ); document.write( " $\"R%5Bf%5D%2A4=V\"$
\n" ); document.write( " $\"R%5Bf%5D=V%2F4\"$
\n" ); document.write( "Find the drain rate,
\n" ); document.write( " $\"R%5Bd%5D%2At=V\"$
\n" ); document.write( " $\"R%5Bd%5D%2A6=V\"$
\n" ); document.write( " $\"R%5Bd%5D=V%2F6\"$
\n" ); document.write( "Now find the time to fill the tank when both valves are open,
\n" ); document.write( " $\"%28R%5Bf%5D-R%5Bd%5D%29%2At=V\"$
\n" ); document.write( " $\"%28V%2F4-V%2F6%29%2At=V\"$
\n" ); document.write( " $\"%281%2F4-1%2F6%29%2At=1\"$
\n" ); document.write( " $\"%283%2F12-2%2F12%29%2At=1\"$
\n" ); document.write( " $\"%281%2F12%29%2At=1\"$
\n" ); document.write( " $\"highlight%28t=12%29\"$ hours
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