document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=794728>Question 794728</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A water tank can be filled by a gasoline fueled water pump in 28 minutes and by an electric pump in 21 minutes. How long would it take to fill the tank if both pumps were used? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #480737 by </B><A HREF=/tutors/aboutme.mpl?userid=Cromlix><B>Cromlix(4381)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Cromlix><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=Cromlix><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=480737\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Gas fuelled water pump takes 28 minutes<BR>\n" );
document.write( "Electric pump takes 21 minutes<BR>\n" );
document.write( "Gas pump takes 1/28 job/min<BR>\n" );
document.write( "Electric pump takes 1/21 job/min<BR>\n" );
document.write( "Together rate = 1/x job/min<BR>\n" );
document.write( "1/28 + 1/21 = 1/x<BR>\n" );
document.write( "Common denominator = 588x<BR>\n" );
document.write( "21x + 28x = 588<BR>\n" );
document.write( "49x = 588<BR>\n" );
document.write( "x = 12<BR>\n" );
document.write( "So together both pumps will<BR>\n" );
document.write( "fill the tank in 12 minutes.<BR>\n" );
document.write( "Hope this helps.<BR>\n" );
document.write( ":-) </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );