document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=899874>Question 899874</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A water tank can be emptied by using one pump for 5 hours. A second, smaller pump can empty the tank in 7 hours. If the larger pump is started at 1:00 P.M., how much time should pass until the smaller pump is started so that the tank will be emptied at 5:00 P.M.?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #545631 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=545631\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A water tank can be emptied by using one pump for 5 hours. A second, smaller pump can empty the tank in 7 hours. If the larger pump is started at 1:00 P.M., how much time should pass until the smaller pump is started so that the tank will be emptied at 5:00 P.M.? <BR>\n" );
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document.write( "Larger pump rate:: 1/5 tank/hr<BR>\n" );
document.write( "Smaller pump rate:: 1/7 tank/hr<BR>\n" );
document.write( "Together rate:: (1/5)+(1/7) = 12/35 tank/hr<BR>\n" );
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document.write( "Equation:<BR>\n" );
document.write( "Larger for x hrs + both for (4-x) hrs = 1 job<BR>\n" );
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document.write( "(1/5)x + (12/35)(4-x) = 1 tank<BR>\n" );
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document.write( "Multiply thru by 35 to get:<BR>\n" );
document.write( "7x + 12(4-x) = 35<BR>\n" );
document.write( "7x + 48 - 12x = 35<BR>\n" );
document.write( "-5x = -13<BR>\n" );
document.write( "x = 13/5 hrs = 2 hrs 36 minutes<BR>\n" );
document.write( "4-x = 1 hr 24 minutes<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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