document.write( "Question 125341This question is from textbook algebra: structure and method: book1
\n" ); document.write( ": the fill pipe for a tank can fill it in 4 hours, and the drain pipe can do it in 2. If both pipes are accidentally opened, how long will it take to drain a half filled tank? HELP!!! the answer is 2 hours, but don't know how to get there. HELP!!! \n" ); document.write( "
Algebra.Com's Answer #91855 by stanbon(75887)\"\" \"About 
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the fill pipe for a tank can fill it in 4 hours, and the drain pipe can do it in 2. If both pipes are accidentally opened, how long will it take to drain a half filled tank?
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\n" ); document.write( "Fill Pipe DATA:
\n" ); document.write( "Time = 4 hrs/job ; Rate = 1/4 job/hr
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\n" ); document.write( "Drain Pipe DATA:
\n" ); document.write( "Time = 2 hrs/job ; Rate = 1/2 job/hr
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\n" ); document.write( "Together DATA;
\n" ); document.write( "Time = x hrs/job ; Rate = 1/x job/hr
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\n" ); document.write( "EQUATION:
\n" ); document.write( "Drain Rate - Fill Rate = together rate
\n" ); document.write( "1/2 - 1/4 = 1/x
\n" ); document.write( "Multiply thru by 4x to get:
\n" ); document.write( "2x - x = 4
\n" ); document.write( "x = 4 hrs to empty a full tank.
\n" ); document.write( "Therefore 2 hrs to empty a half tank.
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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