document.write( "Question 993128: Pipe A can fill a tank alone in 5 hours and Pipe B can fill the tank alone in 4 hours. A drain pipe (Pipe C) can empty the tank in 20 hours. With all three Pipes open, how long will it take to fill the tank \n" ); document.write( "
Algebra.Com's Answer #612486 by ikleyn(52803)\"\" \"About 
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\n" ); document.write( "\"1%2F5\" + \"1%2F4\" - \"1%2F20\" = \"4%2F20+%2B+5%2F20+-+1%2F20\" = \"%284%2B5-1%29%2F20\" = \"8%2F20\" = \"2%2F5\".\r
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\n" ); document.write( "\n" ); document.write( "Hence, it will take \"5%2F2\" = \"2\"\"1%2F2\" hours.\r
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\n" ); document.write( "\n" ); document.write( "It is a joint work problem.\r
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\n" ); document.write( "\n" ); document.write( "For more solved problems of this type see the lesson  Using fractions to solve word problems on joint work  in this site. \r
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\n" ); document.write( "\n" ); document.write( "It is free of charge and without registration.\r
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\n" ); document.write( "\n" ); document.write( "Good luck!\r
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