document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=783272>Question 783272</A>: <I><SPAN STYLE=\"word-break: break-all;\"> One pipe can fill a pool in 9 hours and another pipe can fill the same pool in 12 hours. To fill up the pool, only the first pipe was turned on. After three hours it broke down, and the second pipe was automatically turned on.<BR>\n" );
document.write( "a) How many hours did it take to fill up the pool?<BR>\n" );
document.write( "b) Hom many hours would it take to fill up the pool if the two pipes started to work together? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #476654 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=476654\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> One pipe can fill a pool in 9 hours and another pipe can fill the same pool in 12 hours. To fill up the pool, only the first pipe was turned on. After three hours it broke down, and the second pipe was automatically turned on.<BR>\n" );
document.write( "a) How many hours did it take to fill up the pool?<BR>\n" );
document.write( "b) Hom many hours would it take to fill up the pool if the two pipes started to work together?\r<BR>\n" );
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document.write( "pipe I does 1/9 of the job in 1hour\r<BR>\n" );
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document.write( "In 3 hours it does 3/9 =>1/3 of the job\r<BR>\n" );
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document.write( "Balance job = 1-1/3 = 2/3 of the job.\r<BR>\n" );
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document.write( "Pipe II does 1/12 of the job in 1 hour\r<BR>\n" );
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document.write( "to do 1/3 of the job it will take (1/3)/(1/12) = 4 hours\r<BR>\n" );
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document.write( "Total time = 3 + 4 = 7 hours\r<BR>\n" );
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document.write( "Together they do 1/9 + 1/12 of the job in 1 hour\r<BR>\n" );
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document.write( "so they do 7/36 of the job in 1 hour\r<BR>\n" );
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document.write( "to complete the job they will take 36/7 hours\r<BR>\n" );
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document.write( "5.14 hours\r<BR>\n" );
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document.write( " </SPAN>\n" );
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