document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=136731>Question 136731</A>: <I><SPAN STYLE=\"word-break: break-all;\"> not sure if in right category<BR>\n" );
document.write( "but when the question is like jill does this in 30 min<BR>\n" );
document.write( "bob does it in 45<BR>\n" );
document.write( "sue takes an hour and a half<BR>\n" );
document.write( "how long does it take all of them to do it together<BR>\n" );
document.write( "i have no idea how to solve this problem </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #100093 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=100093\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> jill does this in 30 min<BR>\n" );
document.write( "bob does it in 45<BR>\n" );
document.write( "sue takes an hour and a half<BR>\n" );
document.write( "how long does it take all of them to do it together<BR>\n" );
document.write( "---------------<BR>\n" );
document.write( "You have to realize you cannot add times; you have to add rates.<BR>\n" );
document.write( "--------------<BR>\n" );
document.write( "Jill DATA:<BR>\n" );
document.write( "Time = 30 min/job ; Rate = 1/30 job/min<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "Bob DATA:<BR>\n" );
document.write( "Time = 45 min/job ; Rate = 1/45 job/min<BR>\n" );
document.write( "-----------------<BR>\n" );
document.write( "Sue DATA:<BR>\n" );
document.write( "Time = 90 min ; Rate = 1/90 job/min<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "Together DATA:<BR>\n" );
document.write( "Time = x min/job ; Rate = 1/x job/min<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "EQUATION:<BR>\n" );
document.write( "rate + rate + rate = together rate<BR>\n" );
document.write( "1/30 + 1/45 + 1/90 = 1/x<BR>\n" );
document.write( "Multiply thru by 90x to get:<BR>\n" );
document.write( "3x + 2x + x = 90<BR>\n" );
document.write( "6x = 90 <BR>\n" );
document.write( "x = 15 (amount of time to do the job if they work together)<BR>\n" );
document.write( "=====================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );