document.write( "Question 244863: A tank can be filled by one pipe in four hours and by a second pipe in six hours;and when it is full,the tank can be drained by a third pipe in three hours.If the tank is empty and all three pipes are open,in how many hours will the tank be filled? \n" ); document.write( "

Algebra.Com's Answer #179144 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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A tank can be filled by one pipe in four hours and by a second pipe in six hours;and when it is full,the tank can be drained by a third pipe in three hours.
\n" ); document.write( "If the tank is empty and all three pipes are open,in how many hours will the tank be filled?
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\n" ); document.write( "Just like a \"shared work problem, except the drain fraction is subtracted
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\n" ); document.write( "Let t = time to fill with all pipes open
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\n" ); document.write( "Let the completed job (a full pool) = 1
\n" ); document.write( ":
\n" ); document.write( " $\"t%2F4\"$ + $\"t%2F6\"$ - $\"t%2F3\"$ = 1
\n" ); document.write( "Multiply by 12 to clear the fractions
\n" ); document.write( "3t + 2t - 4t = 12
\n" ); document.write( "t = 12 hrs to fill the pool
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\n" ); document.write( "Check solution on a calc
\n" ); document.write( "12/4 + 12/6 - 12/3 =
\n" ); document.write( "3 + 2 - 4 = 1
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