document.write( "Question 1003410: A small pipe can fill a tank in 8 min more time than it takes a larger pipe to fill the same tank. Working together, the pipes can fill the tank in 3 min. How long would it take each pipe, working alone, to fill the tank?\r
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Algebra.Com's Answer #620202 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! A small pipe can fill a tank in 8 min more time than it takes a larger pipe to fill the same tank. \n" ); document.write( " Working together, the pipes can fill the tank in 3 min. \n" ); document.write( " How long would it take each pipe, working alone, to fill the tank? \n" ); document.write( ": \n" ); document.write( "let t = time for the larger pipe to fill the tank alone \n" ); document.write( "then \n" ); document.write( "(t+8) = time for the smaller pipe to do it \n" ); document.write( ": \n" ); document.write( "let the completed job = 1 (a full tank) \n" ); document.write( " \n" ); document.write( "multiply by t(t+8), cancel the denominators and you have \n" ); document.write( "3(t+8) + 3t = t(t+8) \n" ); document.write( "3t + 24 + 3t = t^2 + 8t \n" ); document.write( "Combine like terms on the right \n" ); document.write( "0 = t^2 + 8t - 6t - 24 \n" ); document.write( "A quadratic equation \n" ); document.write( "t^2 + 2t - 24 = 0 \n" ); document.write( "Factors to \n" ); document.write( "(t+6)(t-4) = 0 \n" ); document.write( "We only want the positive solution here \n" ); document.write( "t = 4 min for the larger pipe to fill the tank \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "Check solution (small pipe requires 12 min) \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |